From patchwork Wed Apr 27 22:48:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829618 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB10AC43217 for ; Wed, 27 Apr 2022 22:52:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238416AbiD0Wzn (ORCPT ); Wed, 27 Apr 2022 18:55:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238242AbiD0Wxo (ORCPT ); Wed, 27 Apr 2022 18:53:44 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 379BE8A30C; Wed, 27 Apr 2022 15:50:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=r/T7YOY0VHwWAfHSEqxJa3Wt3qfvSExYRCUKLKE/qpM=; b=XhhicIlaxPAENQgGkNSZu/8JWa MoKMtLET2WEey/cUMjdoOeeZp/qIHF9AnIAQ1U9UG9ceTx5YsNvbqlEug3W8sTqjMADP3kqZkWGXE 81ePHhsZB9/Fl6O5VwXVIzqdUd2GxbFqpTJI3oISOjep5UHhEIJ1gEAyfbzeKWGz11qqm1H8SqNmy PIXViapEJaVN3g1qVA0ll8xOHoXY2Fth5HpQAgahG3Orvdyx32C20SUgZY0+6ymNqW2eIcskQ9hv0 PnRYqaVu+GNdXU/wxDKHHXg22u4+P2b/VN7O5/RK6RnCNvbziWOBIpkgY1JIKXd1EMfFHtVMCWu3y LPmztM1w==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqTt-0001xj-VW; Thu, 28 Apr 2022 00:49:58 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, "David P . Reed" , Paolo Bonzini , Sean Christopherson Subject: [PATCH 01/30] x86/crash,reboot: Avoid re-disabling VMX in all CPUs on crash/restart Date: Wed, 27 Apr 2022 19:48:55 -0300 Message-Id: <20220427224924.592546-2-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org In the panic path we have a list of functions to be called, the panic notifiers - such callbacks perform various actions in the machine's last breath, and sometimes users want them to run before kdump. We have the parameter "crash_kexec_post_notifiers" for that. When such parameter is used, the function "crash_smp_send_stop()" is executed to poweroff all secondary CPUs through the NMI-shootdown mechanism; part of this process involves disabling virtualization features in all CPUs (except the main one). Now, in the emergency restart procedure we have also a way of disabling VMX in all CPUs, using the same NMI-shootdown mechanism; what happens though is that in case we already NMI-disabled all CPUs, the emergency restart fails due to a second addition of the same items in the NMI list, as per the following log output: sysrq: Trigger a crash Kernel panic - not syncing: sysrq triggered crash [...] Rebooting in 2 seconds.. list_add double add: new=, prev=, next=. ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:29! invalid opcode: 0000 [#1] PREEMPT SMP PTI In order to reproduce the problem, users just need to set the kernel parameter "crash_kexec_post_notifiers" *without* kdump set in any system with the VMX feature present. Since there is no benefit in re-disabling VMX in all CPUs in case it was already done, this patch prevents that by guarding the restart routine against doubly issuing NMIs unnecessarily. Notice we still need to disable VMX locally in the emergency restart. Fixes: ed72736183c4 ("x86/reboot: Force all cpus to exit VMX root if VMX is supported) Fixes: 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump friendly version in panic path") Cc: David P. Reed Cc: Hidehiro Kawai Cc: Paolo Bonzini Cc: Sean Christopherson Signed-off-by: Guilherme G. Piccoli --- arch/x86/include/asm/cpu.h | 1 + arch/x86/kernel/crash.c | 8 ++++---- arch/x86/kernel/reboot.c | 14 ++++++++++++-- 3 files changed, 17 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index 86e5e4e26fcb..b6a9062d387f 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -36,6 +36,7 @@ extern int _debug_hotplug_cpu(int cpu, int action); #endif #endif +extern bool crash_cpus_stopped; int mwait_usable(const struct cpuinfo_x86 *); unsigned int x86_family(unsigned int sig); diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index e8326a8d1c5d..71dd1a990e8d 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -42,6 +42,8 @@ #include #include +bool crash_cpus_stopped; + /* Used while preparing memory map entries for second kernel */ struct crash_memmap_data { struct boot_params *params; @@ -108,9 +110,7 @@ void kdump_nmi_shootdown_cpus(void) /* Override the weak function in kernel/panic.c */ void crash_smp_send_stop(void) { - static int cpus_stopped; - - if (cpus_stopped) + if (crash_cpus_stopped) return; if (smp_ops.crash_stop_other_cpus) @@ -118,7 +118,7 @@ void crash_smp_send_stop(void) else smp_send_stop(); - cpus_stopped = 1; + crash_cpus_stopped = true; } #else diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index fa700b46588e..2fc42b8402ac 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -589,8 +589,18 @@ static void native_machine_emergency_restart(void) int orig_reboot_type = reboot_type; unsigned short mode; - if (reboot_emergency) - emergency_vmx_disable_all(); + /* + * We can reach this point in the end of panic path, having + * NMI-disabled all secondary CPUs. This process involves + * disabling the CPU virtualization technologies, so if that + * is the case, we only miss disabling the local CPU VMX... + */ + if (reboot_emergency) { + if (!crash_cpus_stopped) + emergency_vmx_disable_all(); + else + cpu_emergency_vmxoff(); + } tboot_shutdown(TB_SHUTDOWN_REBOOT); From patchwork Wed Apr 27 22:48:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829617 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2974FC43219 for ; Wed, 27 Apr 2022 22:52:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238126AbiD0Wzl (ORCPT ); Wed, 27 Apr 2022 18:55:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238241AbiD0Wxo (ORCPT ); Wed, 27 Apr 2022 18:53:44 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7757C8A305; Wed, 27 Apr 2022 15:50:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=9bJIN4/MOEhLx8CsVfKAquGTzb1mVDbHr+j6ymCNHAs=; b=S+EoVVMbG0R6l0pBfRnMsKZosp 2PXBHwhmghS5Lvs4v4GQMUSqpGyoQ5U6Zbnyj6sMhUP4BCGILxO7PkeMyVqV/H8eeh+l7ihT1MYQn 6lRWijWvq/MbBgY8W5xo5rf6VIJ8bQ3A6HUNn+RlRorsijlroe/vsascbDWK+dCTLeTv/edmbXzZt IkkQl7Ezob0EK5zEWLgIk+XPPHoVSiw2Ov7kaRBDa36NQrRgmO2O3HFxvBLZEYb5QzmHEcsWLMOdr YdjDzKF3as62X+/HBzxjW/bJqz3Ux15HOHGOCZtJDgeQcPUWNNi8PdpLZsxk0QJWHs39xjqIBwc58 XGSV7jaw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqU9-0001ye-3z; Thu, 28 Apr 2022 00:50:14 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Marc Zyngier , Russell King Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Wed, 27 Apr 2022 19:48:56 -0300 Message-Id: <20220427224924.592546-3-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); From patchwork Wed Apr 27 22:48:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829613 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C13CC4332F for ; Wed, 27 Apr 2022 22:51:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238736AbiD0Wyj (ORCPT ); Wed, 27 Apr 2022 18:54:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238247AbiD0Wyd (ORCPT ); Wed, 27 Apr 2022 18:54:33 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5912D8AE7C; Wed, 27 Apr 2022 15:50:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=jw69MD++mJtoVz+5OF/yDyT7SM6GG1QVsO5qZnTbfPY=; b=R4BaLs+44BYJptao8GvC8ttDH3 QBY0eMxhKSzWFCpxMbR+Fbp293MCB3zvPYgTPMf/b3OkQdSjP24E3L8e4Mxpy4tg+aM7LX40+eANn E9NmhqtSLVcTKfq6OAtiABfZVuEeL7pK/Jggwsb0Z66SwiIPgUgdk8N8FAOWtcyDE4pUFXnvlOs4u KY15nvIzaU7LDhXzbLelthG04bdK8jQeGFwa+aWfBFuZkkmcHkGvkm9AzL5O497raBTZiIXIwFkMO bBhCSNyrOC33WN5GrpTyqWn82roSYAhC1Njfns6EapEQdXDs5qCmdq3kXZk6bj6zjDvwVdiy1jwJ3 PjTlDVgw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqUS-0001zw-SF; Thu, 28 Apr 2022 00:50:33 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Arjan van de Ven , Cong Wang , Sebastian Andrzej Siewior , Valentin Schneider , Xiaoming Ni Subject: [PATCH 03/30] notifier: Add panic notifiers info and purge trailing whitespaces Date: Wed, 27 Apr 2022 19:48:57 -0300 Message-Id: <20220427224924.592546-4-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Although many notifiers are mentioned in the comments, the panic notifiers infrastructure is not. Also, the file contains some trailing whitespaces. This commit fix both issues. Cc: Arjan van de Ven Cc: Cong Wang Cc: Sebastian Andrzej Siewior Cc: Valentin Schneider Cc: Xiaoming Ni Signed-off-by: Guilherme G. Piccoli --- include/linux/notifier.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 87069b8459af..0589896fc7bd 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -201,12 +201,12 @@ static inline int notifier_to_errno(int ret) /* * Declared notifiers so far. I can imagine quite a few more chains - * over time (eg laptop power reset chains, reboot chain (to clean + * over time (eg laptop power reset chains, reboot chain (to clean * device units up), device [un]mount chain, module load/unload chain, - * low memory chain, screenblank chain (for plug in modular screenblankers) + * low memory chain, screenblank chain (for plug in modular screenblankers) * VC switch chains (for loadable kernel svgalib VC switch helpers) etc... */ - + /* CPU notfiers are defined in include/linux/cpu.h. */ /* netdevice notifiers are defined in include/linux/netdevice.h */ @@ -217,6 +217,8 @@ static inline int notifier_to_errno(int ret) /* Virtual Terminal events are defined in include/linux/vt.h. */ +/* Panic notifiers are defined in include/linux/panic_notifier.h. */ + #define NETLINK_URELEASE 0x0001 /* Unicast netlink socket released */ /* Console keyboard events. From patchwork Wed Apr 27 22:48:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829614 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 367A0C35280 for ; Wed, 27 Apr 2022 22:51:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238889AbiD0Wyo (ORCPT ); Wed, 27 Apr 2022 18:54:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238414AbiD0Wyf (ORCPT ); Wed, 27 Apr 2022 18:54:35 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA47D8CCD3; Wed, 27 Apr 2022 15:51:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=s8xeHJYGrg2PKjTPKivxQn37LuEP6tnBzN9Ru5ARxEw=; b=itLofTxVD3jMCMG1QHrJKsVczn vbwUlm+NWg0pMSOCtSjWETMXDXA/dO9ti0V72q001TMmb2gIzR2yZduw7qvMkCQ0akMjJfPi2/PQc iUqIhedKtPpwa0f3Qs25a8tdm2oshD1/KMZCL+mdxqH7vtpZXZFld+eSj+8owBfmLjMNmktzOqSfY dTb/ic9+j716feaFlMGDFCnVL8lNNI9bMH1gzqsKPsNg72iLmPQmwnJD7EfxHW7NQoAv8T+6Y8VEH 2ohazyjoc9Z+MNXm7Lr7Bh3GLxJ6zmDCTC3SRdi9P8jirAP5MyZi4cLioUm7IG4Ag3/IwiKZ9+K4K 3P27PVmg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqUi-00020p-0e; Thu, 28 Apr 2022 00:50:49 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Ard Biesheuvel , David Gow , Evan Green , Julius Werner Subject: [PATCH 04/30] firmware: google: Convert regular spinlock into trylock on panic path Date: Wed, 27 Apr 2022 19:48:58 -0300 Message-Id: <20220427224924.592546-5-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the gsmi driver registers a panic notifier as well as reboot and die notifiers. The callbacks registered are called in atomic and very limited context - for instance, panic disables preemption, local IRQs and all other CPUs that aren't running the current panic function. With that said, taking a spinlock in this scenario is a dangerous invitation for a deadlock scenario. So, we fix that in this commit by changing the regular spinlock with a trylock, which is a safer approach. Fixes: 74c5b31c6618 ("driver: Google EFI SMI") Cc: Ard Biesheuvel Cc: David Gow Cc: Evan Green Cc: Julius Werner Signed-off-by: Guilherme G. Piccoli --- drivers/firmware/google/gsmi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c index adaa492c3d2d..b01ed02e4a87 100644 --- a/drivers/firmware/google/gsmi.c +++ b/drivers/firmware/google/gsmi.c @@ -629,7 +629,10 @@ static int gsmi_shutdown_reason(int reason) if (saved_reason & (1 << reason)) return 0; - spin_lock_irqsave(&gsmi_dev.lock, flags); + if (!spin_trylock_irqsave(&gsmi_dev.lock, flags)) { + rc = -EBUSY; + goto out; + } saved_reason |= (1 << reason); @@ -646,6 +649,7 @@ static int gsmi_shutdown_reason(int reason) spin_unlock_irqrestore(&gsmi_dev.lock, flags); +out: if (rc < 0) printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n"); else From patchwork Wed Apr 27 22:48:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829616 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B167C433FE for ; Wed, 27 Apr 2022 22:51:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238641AbiD0WzA (ORCPT ); Wed, 27 Apr 2022 18:55:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237853AbiD0Wyi (ORCPT ); Wed, 27 Apr 2022 18:54:38 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30A968CCF2; Wed, 27 Apr 2022 15:51:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=/X9VGFpkqSi0Xw+sb2fnqT5ti0fEX/+xmh5q7q7MhDY=; b=p3QOIFADQeeHCVp8bxPKwO62s+ EGcZOVKN2qbhBt1Pf/EZXw+tkBx2x9DRVMO1uTp94JqIADubO77jiICP/E04L/nn99FEYBzZb+44L /kz24xVDrX4FFqomkvxzWUTFlHhE4ZhZCfkHWBQr0/Lzkqr3CE/w4r7fAtX83L8f0pEarK5Qx6XYH 4zbdyCjIZQkKS6mh2t53k79tPqORut15Ek94GDPyIzx6i+d57M9a0UcH7EVEXkkbVPk2r+5s4ram2 N0+1/N2WpK9qFZ8QFj+vJFSqHIZNJD4YgbbIqqLYxl+DJIQthPO2tybUvOHdIFVD8Tw3e7+DHlkve LuLH0yww==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqV1-000228-53; Thu, 28 Apr 2022 00:51:08 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Christophe JAILLET , Mihai Carabas , Shile Zhang , Wang ShaoBo , zhenwei pi Subject: [PATCH 05/30] misc/pvpanic: Convert regular spinlock into trylock on panic path Date: Wed, 27 Apr 2022 19:48:59 -0300 Message-Id: <20220427224924.592546-6-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The pvpanic driver relies on panic notifiers to execute a callback on panic event. Such function is executed in atomic context - the panic function disables local IRQs, preemption and all other CPUs that aren't running the panic code. With that said, it's dangerous to use regular spinlocks in such path, as introduced by commit b3c0f8774668 ("misc/pvpanic: probe multiple instances"). This patch fixes that by replacing regular spinlocks with the trylock safer approach. It also fixes an old comment (about a long gone framebuffer code) and the notifier priority - we should execute hypervisor notifiers early, deferring this way the panic action to the hypervisor, as expected by the users that are setting up pvpanic. Fixes: b3c0f8774668 ("misc/pvpanic: probe multiple instances") Cc: Christophe JAILLET Cc: Mihai Carabas Cc: Shile Zhang Cc: Wang ShaoBo Cc: zhenwei pi Signed-off-by: Guilherme G. Piccoli --- drivers/misc/pvpanic/pvpanic.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c index 4b8f1c7d726d..049a12006348 100644 --- a/drivers/misc/pvpanic/pvpanic.c +++ b/drivers/misc/pvpanic/pvpanic.c @@ -34,7 +34,9 @@ pvpanic_send_event(unsigned int event) { struct pvpanic_instance *pi_cur; - spin_lock(&pvpanic_lock); + if (!spin_trylock(&pvpanic_lock)) + return; + list_for_each_entry(pi_cur, &pvpanic_list, list) { if (event & pi_cur->capability & pi_cur->events) iowrite8(event, pi_cur->base); @@ -55,9 +57,13 @@ pvpanic_panic_notify(struct notifier_block *nb, unsigned long code, void *unused return NOTIFY_DONE; } +/* + * Call our notifier very early on panic, deferring the + * action taken to the hypervisor. + */ static struct notifier_block pvpanic_panic_nb = { .notifier_call = pvpanic_panic_notify, - .priority = 1, /* let this called before broken drm_fb_helper() */ + .priority = INT_MAX, }; static void pvpanic_remove(void *param) From patchwork Wed Apr 27 22:49:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829615 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D134C4167B for ; Wed, 27 Apr 2022 22:51:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238990AbiD0Wyu (ORCPT ); Wed, 27 Apr 2022 18:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238880AbiD0Wym (ORCPT ); Wed, 27 Apr 2022 18:54:42 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 842C58CCD3; Wed, 27 Apr 2022 15:51:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=5Wppui/4+4q1PWThaAiWQx32MHyg/obGwoGJE8vkLrA=; b=IRi7rvSSPrrOoy0S56lz2UJRtC W1l3fBj8xVxgLD6KW8zqEI0EfCOiXJW5ZsYXn2WVzqXNxfRkE81Vja/726PNP5gfd+ffe5+sSmine oDSQIDYY0LQtz/eUpNO/O3flF5w2323kd1e2RLGfs/+wuvi6OZjtA/cAWJ8y4DX82MWtYSxfkdu78 HNn3Scwjr+UIudJHWW8i9wi/BmFAgD6nNrsW4GexdH6x6p4zIq9laE/2q1VZR7YM8s/7fvEfIhVyD gNu+c9943row/xgSKe8GkhslCs6aT6+524Fp09jB/vhA283Kkt9uCVO689z6MyVp8qdL3zZfdmmrO nvvrYfqw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqVG-00023b-GJ; Thu, 28 Apr 2022 00:51:23 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Brian Norris , Doug Berger , Florian Fainelli , Justin Chen , Lee Jones , Markus Mayer Subject: [PATCH 06/30] soc: bcm: brcmstb: Document panic notifier action and remove useless header Date: Wed, 27 Apr 2022 19:49:00 -0300 Message-Id: <20220427224924.592546-7-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The panic notifier of this driver is very simple code-wise, just a memory write to a special position with some numeric code. But this is not clear from the semantic point-of-view, and there is no public documentation about that either. After discussing this in the mailing-lists [0] and having Florian explained it very well, this patch just document that in the code for the future generations asking the same questions. Also, it removes a useless header. [0] https://lore.kernel.org/lkml/781cafb0-8d06-8b56-907a-5175c2da196a@gmail.com Fixes: 0b741b8234c8 ("soc: bcm: brcmstb: Add support for S2/S3/S5 suspend states (ARM)") Cc: Brian Norris Cc: Doug Berger Cc: Florian Fainelli Cc: Justin Chen Cc: Lee Jones Cc: Markus Mayer Signed-off-by: Guilherme G. Piccoli Acked-by: Florian Fainelli --- drivers/soc/bcm/brcmstb/pm/pm-arm.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/soc/bcm/brcmstb/pm/pm-arm.c b/drivers/soc/bcm/brcmstb/pm/pm-arm.c index 3cbb165d6e30..870686ae042b 100644 --- a/drivers/soc/bcm/brcmstb/pm/pm-arm.c +++ b/drivers/soc/bcm/brcmstb/pm/pm-arm.c @@ -25,7 +25,6 @@ #include #include #include -#include #include #include #include @@ -664,7 +663,20 @@ static void __iomem *brcmstb_ioremap_match(const struct of_device_id *matches, return of_io_request_and_map(dn, index, dn->full_name); } - +/* + * The AON is a small domain in the SoC that can retain its state across + * various system wide sleep states and specific reset conditions; the + * AON DATA RAM is a small RAM of a few words (< 1KB) which can store + * persistent information across such events. + * + * The purpose of the below panic notifier is to help with notifying + * the bootloader that a panic occurred and so that it should try its + * best to preserve the DRAM contents holding that buffer for recovery + * by the kernel as opposed to wiping out DRAM clean again. + * + * Reference: comment from Florian Fainelli, at + * https://lore.kernel.org/lkml/781cafb0-8d06-8b56-907a-5175c2da196a@gmail.com + */ static int brcmstb_pm_panic_notify(struct notifier_block *nb, unsigned long action, void *data) { From patchwork Wed Apr 27 22:49:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829619 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 257DBC43217 for ; Wed, 27 Apr 2022 22:53:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238986AbiD0W4g (ORCPT ); Wed, 27 Apr 2022 18:56:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238520AbiD0Wy7 (ORCPT ); Wed, 27 Apr 2022 18:54:59 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28D6F8CD97; Wed, 27 Apr 2022 15:51:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=sBnzQEgOETevrWvoFDe4UXYaoyJvnokumNTnFd8nYd4=; b=C3WoMDzHemUiz3TJonrj4OLB2r FSxQF+F2lHHptNuVBTghKMJZClefE6Imxei6ehl090Dy2iIiwWYXrKfz8k6+wORL9DMg3LEbLg3HV Yy5IDocQKz78CwwV1x1BjunLLiApngptGwnQE+MM0c5kIHbxgr5QD1BtqzYPoELgJZUScA99Ow0T5 DgoMAXPJxcpvr2MM73b5S2P6pfeIYXcyYWBlbiqaBO38Mb9qP/Auq8X4+iMlX3NAoRdIHY9DVHKc8 OvjiTLZuxC2PHt1XEzIKelV5l8TbSCfHnuQVB2KdJOLt6lDAQzFhqrTn+CsXTsATCFcE2SPeUMfAC eC7wzCXg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqVW-000250-IT; Thu, 28 Apr 2022 00:51:39 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Thomas Bogendoerfer Subject: [PATCH 07/30] mips: ip22: Reword PANICED to PANICKED and remove useless header Date: Wed, 27 Apr 2022 19:49:01 -0300 Message-Id: <20220427224924.592546-8-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Many other place in the kernel prefer the latter, so let's keep it consistent in MIPS code as well. Also, removes a useless header. Cc: Thomas Bogendoerfer Signed-off-by: Guilherme G. Piccoli --- arch/mips/sgi-ip22/ip22-reset.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/mips/sgi-ip22/ip22-reset.c b/arch/mips/sgi-ip22/ip22-reset.c index 9028dbbb45dd..8f0861c58080 100644 --- a/arch/mips/sgi-ip22/ip22-reset.c +++ b/arch/mips/sgi-ip22/ip22-reset.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include @@ -41,7 +40,7 @@ static struct timer_list power_timer, blink_timer, debounce_timer; static unsigned long blink_timer_timeout; -#define MACHINE_PANICED 1 +#define MACHINE_PANICKED 1 #define MACHINE_SHUTTING_DOWN 2 static int machine_state; @@ -112,7 +111,7 @@ static void debounce(struct timer_list *unused) return; } - if (machine_state & MACHINE_PANICED) + if (machine_state & MACHINE_PANICKED) sgimc->cpuctrl0 |= SGIMC_CCTRL0_SYSINIT; enable_irq(SGI_PANEL_IRQ); @@ -120,7 +119,7 @@ static void debounce(struct timer_list *unused) static inline void power_button(void) { - if (machine_state & MACHINE_PANICED) + if (machine_state & MACHINE_PANICKED) return; if ((machine_state & MACHINE_SHUTTING_DOWN) || @@ -167,9 +166,9 @@ static irqreturn_t panel_int(int irq, void *dev_id) static int panic_event(struct notifier_block *this, unsigned long event, void *ptr) { - if (machine_state & MACHINE_PANICED) + if (machine_state & MACHINE_PANICKED) return NOTIFY_DONE; - machine_state |= MACHINE_PANICED; + machine_state |= MACHINE_PANICKED; blink_timer_timeout = PANIC_FREQ; blink_timeout(&blink_timer); From patchwork Wed Apr 27 22:49:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829681 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79D73C433F5 for ; Wed, 27 Apr 2022 22:53:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238965AbiD0W5G (ORCPT ); Wed, 27 Apr 2022 18:57:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238132AbiD0W44 (ORCPT ); Wed, 27 Apr 2022 18:56:56 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E406090CC5; Wed, 27 Apr 2022 15:52:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=/cdg0sKCsuwzrOmixxbC1Q4JQ/fbIS+o0nd/6r3SqdQ=; b=Ms53zbjgbkvE/VbvvERWDhiSlK xnfSZ26duHs4sJGmX9AjyiOpVrZ24qlvncFPTQgx0Ak1/K+qg/q6M3lNqtXBQSywskWJGGXxxZsyH 0ZCt9ADqjTi/3V+XCpSLOfo1kVbAL88rsa3CWloXQYrPcKcjm0fr5wkBOKZGIirx4MPHlXEq/lSP6 Wauj7ki9eqiIN/DWOEVCrOIQ5CDDEHA0P4AiVRkbPc3MLQuGkkZQLCDxyedC8rV+CPmlMqMLZGK7O pj27Q1YpHqsziDeg78TsiM6RPMIm39rOPoY53108P/vAvRYTx1t1bv7hv+1+u3acH1fsI00wIEzlf mvZOITKg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqVm-00026W-Rl; Thu, 28 Apr 2022 00:51:55 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Benjamin Herrenschmidt , Hari Bathini , Michael Ellerman , Nicholas Piggin , Paul Mackerras Subject: [PATCH 08/30] powerpc/setup: Refactor/untangle panic notifiers Date: Wed, 27 Apr 2022 19:49:02 -0300 Message-Id: <20220427224924.592546-9-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The panic notifiers infrastructure is a bit limited in the scope of the callbacks - basically every kind of functionality is dropped in a list that runs in the same point during the kernel panic path. This is not really on par with the complexities and particularities of architecture / hypervisors' needs, and a refactor is ongoing. As part of this refactor, it was observed that powerpc has 2 notifiers, with mixed goals: one is just a KASLR offset dumper, whereas the other aims to hard-disable IRQs (necessary on panic path), warn firmware of the panic event (fadump) and run low-level platform-specific machinery that might stop kernel execution and never come back. Clearly, the 2nd notifier has opposed goals: disable IRQs / fadump should run earlier while low-level platform actions should run late since it might not even return. Hence, this patch decouples the notifiers splitting them in three: - First one is responsible for hard-disable IRQs and fadump, should run early; - The kernel KASLR offset dumper is really an informative notifier, harmless and may run at any moment in the panic path; - The last notifier should run last, since it aims to perform low-level actions for specific platforms, and might never return. It is also only registered for 2 platforms, pseries and ps3. The patch better documents the notifiers and clears the code too, also removing a useless header. Currently no functionality change should be observed, but after the planned panic refactor we should expect more panic reliability with this patch. Cc: Benjamin Herrenschmidt Cc: Hari Bathini Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul Mackerras Signed-off-by: Guilherme G. Piccoli Reviewed-by: Hari Bathini --- We'd like to thanks specially the MiniCloud infrastructure [0] maintainers, that allow us to test PowerPC code in a very complete, functional and FREE environment (there's no need even for adding a credit card, like many "free" clouds require ¬¬ ). [0] https://openpower.ic.unicamp.br/minicloud arch/powerpc/kernel/setup-common.c | 74 ++++++++++++++++++++++-------- 1 file changed, 54 insertions(+), 20 deletions(-) diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 518ae5aa9410..52f96b209a96 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -23,7 +23,6 @@ #include #include #include -#include #include #include #include @@ -680,8 +679,25 @@ int check_legacy_ioport(unsigned long base_port) } EXPORT_SYMBOL(check_legacy_ioport); -static int ppc_panic_event(struct notifier_block *this, - unsigned long event, void *ptr) +/* + * Panic notifiers setup + * + * We have 3 notifiers for powerpc, each one from a different "nature": + * + * - ppc_panic_fadump_handler() is a hypervisor notifier, which hard-disables + * IRQs and deal with the Firmware-Assisted dump, when it is configured; + * should run early in the panic path. + * + * - dump_kernel_offset() is an informative notifier, just showing the KASLR + * offset if we have RANDOMIZE_BASE set. + * + * - ppc_panic_platform_handler() is a low-level handler that's registered + * only if the platform wishes to perform final actions in the panic path, + * hence it should run late and might not even return. Currently, only + * pseries and ps3 platforms register callbacks. + */ +static int ppc_panic_fadump_handler(struct notifier_block *this, + unsigned long event, void *ptr) { /* * panic does a local_irq_disable, but we really @@ -691,45 +707,63 @@ static int ppc_panic_event(struct notifier_block *this, /* * If firmware-assisted dump has been registered then trigger - * firmware-assisted dump and let firmware handle everything else. + * its callback and let the firmware handles everything else. */ crash_fadump(NULL, ptr); - if (ppc_md.panic) - ppc_md.panic(ptr); /* May not return */ + return NOTIFY_DONE; } -static struct notifier_block ppc_panic_block = { - .notifier_call = ppc_panic_event, - .priority = INT_MIN /* may not return; must be done last */ -}; - -/* - * Dump out kernel offset information on panic. - */ static int dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p) { pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n", kaslr_offset(), KERNELBASE); - return 0; + return NOTIFY_DONE; } +static int ppc_panic_platform_handler(struct notifier_block *this, + unsigned long event, void *ptr) +{ + /* + * This handler is only registered if we have a panic callback + * on ppc_md, hence NULL check is not needed. + * Also, it may not return, so it runs really late on panic path. + */ + ppc_md.panic(ptr); + + return NOTIFY_DONE; +} + +static struct notifier_block ppc_fadump_block = { + .notifier_call = ppc_panic_fadump_handler, + .priority = INT_MAX, /* run early, to notify the firmware ASAP */ +}; + static struct notifier_block kernel_offset_notifier = { - .notifier_call = dump_kernel_offset + .notifier_call = dump_kernel_offset, +}; + +static struct notifier_block ppc_panic_block = { + .notifier_call = ppc_panic_platform_handler, + .priority = INT_MIN, /* may not return; must be done last */ }; void __init setup_panic(void) { + /* Hard-disables IRQs + deal with FW-assisted dump (fadump) */ + atomic_notifier_chain_register(&panic_notifier_list, + &ppc_fadump_block); + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) atomic_notifier_chain_register(&panic_notifier_list, &kernel_offset_notifier); - /* PPC64 always does a hard irq disable in its panic handler */ - if (!IS_ENABLED(CONFIG_PPC64) && !ppc_md.panic) - return; - atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block); + /* Low-level platform-specific routines that should run on panic */ + if (ppc_md.panic) + atomic_notifier_chain_register(&panic_notifier_list, + &ppc_panic_block); } #ifdef CONFIG_CHECK_CACHE_COHERENCY From patchwork Wed Apr 27 22:49:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829682 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 011BDC4167B for ; Wed, 27 Apr 2022 22:54:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239045AbiD0W5t (ORCPT ); Wed, 27 Apr 2022 18:57:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238628AbiD0W5D (ORCPT ); Wed, 27 Apr 2022 18:57:03 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 484EEB247E; Wed, 27 Apr 2022 15:52:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=seVlMlqj/OOgqWCw1tUxCfRyMjTeYr5Z28M++b51Xf4=; b=ZaOL9ZgN+EGmQho6+KGFZHTRbn OaOWIMR4M4pabKtnueiNn0ccKPcDo3HPhyU+dXv5cnfPUStBzfPFVl+jQM59vF4ZhACUpuR43IYXQ ZxDFWoPV6MSwPwBTAmhnCK48+3Rd3s3YxmPfJVkzBknJImEbRwxzoUg95gTvTUorv8vMDdjprmUy3 YkS66FLAwKwDNOu8o7q4f4XVv/vUJe4PGzk68gQ9Mx3uMtXXVmK27/P4rcS4LEEam3214m5o7ahcQ 5LKqcAxUSITnoTva0XbxnJK2lHjf45/V+xGb9BJP25J23hUhWNHPX2AXkANv1NANWHSZgkACdPcYF QXixtySQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqW1-000289-9r; Thu, 28 Apr 2022 00:52:10 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Leo Yan , Mathieu Poirier , Mike Leach , Suzuki K Poulose Subject: [PATCH 09/30] coresight: cpu-debug: Replace mutex with mutex_trylock on panic notifier Date: Wed, 27 Apr 2022 19:49:03 -0300 Message-Id: <20220427224924.592546-10-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The panic notifier infrastructure executes registered callbacks when a panic event happens - such callbacks are executed in atomic context, with interrupts and preemption disabled in the running CPU and all other CPUs disabled. That said, mutexes in such context are not a good idea. This patch replaces a regular mutex with a mutex_trylock safer approach; given the nature of the mutex used in the driver, it should be pretty uncommon being unable to acquire such mutex in the panic path, hence no functional change should be observed (and if it is, that would be likely a deadlock with the regular mutex). Fixes: 2227b7c74634 ("coresight: add support for CPU debug module") Cc: Leo Yan Cc: Mathieu Poirier Cc: Mike Leach Cc: Suzuki K Poulose Signed-off-by: Guilherme G. Piccoli Reviewed-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-cpu-debug.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c index 8845ec4b4402..1874df7c6a73 100644 --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c @@ -380,9 +380,10 @@ static int debug_notifier_call(struct notifier_block *self, int cpu; struct debug_drvdata *drvdata; - mutex_lock(&debug_lock); + /* Bail out if we can't acquire the mutex or the functionality is off */ + if (!mutex_trylock(&debug_lock)) + return NOTIFY_DONE; - /* Bail out if the functionality is disabled */ if (!debug_enable) goto skip_dump; @@ -401,7 +402,7 @@ static int debug_notifier_call(struct notifier_block *self, skip_dump: mutex_unlock(&debug_lock); - return 0; + return NOTIFY_DONE; } static struct notifier_block debug_notifier = { From patchwork Wed Apr 27 22:49:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829683 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C96C6C35274 for ; Wed, 27 Apr 2022 22:54:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239214AbiD0W5u (ORCPT ); Wed, 27 Apr 2022 18:57:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235419AbiD0W53 (ORCPT ); Wed, 27 Apr 2022 18:57:29 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7779B3C57; Wed, 27 Apr 2022 15:52:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=BexKVXcxuZt34azQ5Muv1vJV6tgwpIcW3JsMthwMxfs=; b=BRT/sKLpYXau/Ji4ZqRLBh2wLe Ez82oN0tPhCaeccxvStT4dM/VXWT0UOTgVT7srxju4FTp1lIxHZgITVU09FPE0hwYIbUj79K3InFF c3u/lCG1AZZtsXeU+SEcK9u0pYYem+Sajrhv7s+jR5UPYROYW2E4rHsCktC7o7MuiSwumDe0KTw8O uv2vnGx/4l5xRolhC4zk2RH1ShfOhYp0567tBrYlkHX5Tuh9PS21K9iN1pNYOoy8D+KSBJrTAnUOx BdTF6VrcFln7xzJle98w0XT7WzPU38wHtKJVV73Cz5eypbAomXnD5JiFGfsNH5tWiuiFJ1HH5bqlk bHcrf8AQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqWG-00029R-Tx; Thu, 28 Apr 2022 00:52:25 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Ivan Kokshaysky , Matt Turner , Richard Henderson Subject: [PATCH 10/30] alpha: Clean-up the panic notifier code Date: Wed, 27 Apr 2022 19:49:04 -0300 Message-Id: <20220427224924.592546-11-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The alpha panic notifier has some code issues, not following the conventions of other notifiers. Also, it might halt the machine but still it is set to run as early as possible, which doesn't seem to be a good idea. This patch cleans the code, and set the notifier to run as the latest, following the same approach other architectures are doing. Also, we remove the unnecessary include of a header already included indirectly. Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Richard Henderson Signed-off-by: Guilherme G. Piccoli Reviewed-by: Petr Mladek --- arch/alpha/kernel/setup.c | 36 +++++++++++++++--------------------- 1 file changed, 15 insertions(+), 21 deletions(-) diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index b4fbbba30aa2..d88bdf852753 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -41,19 +41,11 @@ #include #include #endif -#include #include #include #include #include -static int alpha_panic_event(struct notifier_block *, unsigned long, void *); -static struct notifier_block alpha_panic_block = { - alpha_panic_event, - NULL, - INT_MAX /* try to do it first */ -}; - #include #include #include @@ -435,6 +427,21 @@ static const struct sysrq_key_op srm_sysrq_reboot_op = { }; #endif +static int alpha_panic_event(struct notifier_block *this, + unsigned long event, void *ptr) +{ + /* If we are using SRM and serial console, just hard halt here. */ + if (alpha_using_srm && srmcons_output) + __halt(); + + return NOTIFY_DONE; +} + +static struct notifier_block alpha_panic_block = { + .notifier_call = alpha_panic_event, + .priority = INT_MIN, /* may not return, do it last */ +}; + void __init setup_arch(char **cmdline_p) { @@ -1427,19 +1434,6 @@ const struct seq_operations cpuinfo_op = { .show = show_cpuinfo, }; - -static int -alpha_panic_event(struct notifier_block *this, unsigned long event, void *ptr) -{ -#if 1 - /* FIXME FIXME FIXME */ - /* If we are using SRM and serial console, just hard halt here. */ - if (alpha_using_srm && srmcons_output) - __halt(); -#endif - return NOTIFY_DONE; -} - static __init int add_pcspkr(void) { struct platform_device *pd; From patchwork Wed Apr 27 22:49:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829687 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB846C433FE for ; Wed, 27 Apr 2022 22:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237492AbiD0W6h (ORCPT ); Wed, 27 Apr 2022 18:58:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238160AbiD0W5b (ORCPT ); Wed, 27 Apr 2022 18:57:31 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54CFAB3C6F; Wed, 27 Apr 2022 15:52:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=bCeC+folLkdyk3b6apumHxcRwMBwOys8pMRPpqSclew=; b=TqPRVvgSfmMVR610uLcwg2vC34 pLIumny6UC9NAVKrJeC8kjbMxl/tivBCI9wjj++xXokR3qbvfCHXTOfrOaZezN2wYfsTeWwS7JgiC ST58COWgOj0NVLj/RM40gpf1tYeZ+3Akn0o3OOB9wnVZqXRK498bYXNcV51purgIjJ73eodK18ucj +Iyv87VDCsJruNsaOWJAaGmlYU1Av1XSojv9QPvuFZsys/hw7VJ6aN2N3d0SlURJabJe1PgCqptXF Xo2aIypAELGn+aiNCAnoOIj6PgcxN1C5aslHAtr3OG/wMakbb0/ORKtlMkkFaGzr7X86jahmQbl4p VjCzjD3g==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqWU-0002B5-Ub; Thu, 28 Apr 2022 00:52:40 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Anton Ivanov , Johannes Berg , Richard Weinberger Subject: [PATCH 11/30] um: Improve panic notifiers consistency and ordering Date: Wed, 27 Apr 2022 19:49:05 -0300 Message-Id: <20220427224924.592546-12-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the panic notifiers from user mode linux don't follow the convention for most of the other notifiers present in the kernel (indentation, priority setting, numeric return). More important, the priorities could be improved, since it's a special case (userspace), hence we could run the notifiers earlier; user mode linux shouldn't care much with other panic notifiers but the ordering among the mconsole and arch notifier is important, given that the arch one effectively triggers a core dump. This patch fixes that by running the mconsole notifier as the first panic notifier, followed by the architecture one (that coredumps). Also, we remove a useless header inclusion. Cc: Anton Ivanov Cc: Johannes Berg Cc: Richard Weinberger Signed-off-by: Guilherme G. Piccoli --- arch/um/drivers/mconsole_kern.c | 8 +++----- arch/um/kernel/um_arch.c | 8 ++++---- 2 files changed, 7 insertions(+), 9 deletions(-) diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 8ca67a692683..2ea0421bcc3f 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include @@ -846,13 +845,12 @@ static int notify_panic(struct notifier_block *self, unsigned long unused1, mconsole_notify(notify_socket, MCONSOLE_PANIC, message, strlen(message) + 1); - return 0; + return NOTIFY_DONE; } static struct notifier_block panic_exit_notifier = { - .notifier_call = notify_panic, - .next = NULL, - .priority = 1 + .notifier_call = notify_panic, + .priority = INT_MAX, /* run as soon as possible */ }; static int add_notifier(void) diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 0760e24f2eba..4485b1a7c8e4 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -246,13 +246,13 @@ static int panic_exit(struct notifier_block *self, unsigned long unused1, bust_spinlocks(0); uml_exitcode = 1; os_dump_core(); - return 0; + + return NOTIFY_DONE; } static struct notifier_block panic_exit_notifier = { - .notifier_call = panic_exit, - .next = NULL, - .priority = 0 + .notifier_call = panic_exit, + .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */ }; void uml_finishsetup(void) From patchwork Wed Apr 27 22:49:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829684 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 234F6C43219 for ; Wed, 27 Apr 2022 22:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239524AbiD0W6A (ORCPT ); Wed, 27 Apr 2022 18:58:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238092AbiD0W5j (ORCPT ); Wed, 27 Apr 2022 18:57:39 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63AD1B3DF1; Wed, 27 Apr 2022 15:53:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Kr032SD5vU+3986AqF/gyJuhFfnr0rncUaszbIKwr2Y=; b=fBwyO/j+yxT2AymE7SizsCmDjX 1r+REb2uiNLyOmmbv6Nh9J6FxLhB1bfvTpTjG3mgSTFTL8dz34enGcBQdaqLpKSF+I5gGd/nAJUMJ jfyQZXSy1JqEja03OmP72YQEOLiC8m3Lw1UsxeNTdyoogn1QFWiKLBkCPwl7A/i8ZlFDdHuwQzMA1 jTKSmHNDM3VElo6fZPijCzvlYComyxyp1IGRSiaeBrih1Typo5NHSl5Gp5sEACObYkVVo4g3YPBCY BcFTyK5zLHDJeUb/agfenHI/ZzcT83HZfKlj9EnBYJpw9rKnDjMmdBRtHu3w1BfvP2PQydzd7nH74 efngoTDg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqWj-0002CA-PR; Thu, 28 Apr 2022 00:52:54 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Helge Deller , "James E.J. Bottomley" Subject: [PATCH 12/30] parisc: Replace regular spinlock with spin_trylock on panic path Date: Wed, 27 Apr 2022 19:49:06 -0300 Message-Id: <20220427224924.592546-13-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The panic notifiers' callbacks execute in an atomic context, with interrupts/preemption disabled, and all CPUs not running the panic function are off, so it's very dangerous to wait on a regular spinlock, there's a risk of deadlock. This patch refactors the panic notifier of parisc/power driver to make use of spin_trylock - for that, we've added a second version of the soft-power function. Also, some comments were reorganized and trailing white spaces, useless header inclusion and blank lines were removed. Cc: Helge Deller Cc: "James E.J. Bottomley" Signed-off-by: Guilherme G. Piccoli Acked-by: Helge Deller # parisc --- arch/parisc/include/asm/pdc.h | 1 + arch/parisc/kernel/firmware.c | 27 +++++++++++++++++++++++---- drivers/parisc/power.c | 17 ++++++++++------- 3 files changed, 34 insertions(+), 11 deletions(-) diff --git a/arch/parisc/include/asm/pdc.h b/arch/parisc/include/asm/pdc.h index b643092d4b98..7a106008e258 100644 --- a/arch/parisc/include/asm/pdc.h +++ b/arch/parisc/include/asm/pdc.h @@ -83,6 +83,7 @@ int pdc_do_firm_test_reset(unsigned long ftc_bitmap); int pdc_do_reset(void); int pdc_soft_power_info(unsigned long *power_reg); int pdc_soft_power_button(int sw_control); +int pdc_soft_power_button_panic(int sw_control); void pdc_io_reset(void); void pdc_io_reset_devices(void); int pdc_iodc_getc(void); diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c index 6a7e315bcc2e..0e2f70b592f4 100644 --- a/arch/parisc/kernel/firmware.c +++ b/arch/parisc/kernel/firmware.c @@ -1232,15 +1232,18 @@ int __init pdc_soft_power_info(unsigned long *power_reg) } /* - * pdc_soft_power_button - Control the soft power button behaviour - * @sw_control: 0 for hardware control, 1 for software control + * pdc_soft_power_button{_panic} - Control the soft power button behaviour + * @sw_control: 0 for hardware control, 1 for software control * * * This PDC function places the soft power button under software or * hardware control. - * Under software control the OS may control to when to allow to shut - * down the system. Under hardware control pressing the power button + * Under software control the OS may control to when to allow to shut + * down the system. Under hardware control pressing the power button * powers off the system immediately. + * + * The _panic version relies in spin_trylock to prevent deadlock + * on panic path. */ int pdc_soft_power_button(int sw_control) { @@ -1254,6 +1257,22 @@ int pdc_soft_power_button(int sw_control) return retval; } +int pdc_soft_power_button_panic(int sw_control) +{ + int retval; + unsigned long flags; + + if (!spin_trylock_irqsave(&pdc_lock, flags)) { + pr_emerg("Couldn't enable soft power button\n"); + return -EBUSY; /* ignored by the panic notifier */ + } + + retval = mem_pdc_call(PDC_SOFT_POWER, PDC_SOFT_POWER_ENABLE, __pa(pdc_result), sw_control); + spin_unlock_irqrestore(&pdc_lock, flags); + + return retval; +} + /* * pdc_io_reset - Hack to avoid overlapping range registers of Bridges devices. * Primarily a problem on T600 (which parisc-linux doesn't support) but diff --git a/drivers/parisc/power.c b/drivers/parisc/power.c index 456776bd8ee6..8512884de2cf 100644 --- a/drivers/parisc/power.c +++ b/drivers/parisc/power.c @@ -37,7 +37,6 @@ #include #include #include -#include #include #include #include @@ -175,16 +174,21 @@ static void powerfail_interrupt(int code, void *x) -/* parisc_panic_event() is called by the panic handler. - * As soon as a panic occurs, our tasklets above will not be - * executed any longer. This function then re-enables the - * soft-power switch and allows the user to switch off the system +/* + * parisc_panic_event() is called by the panic handler. + * + * As soon as a panic occurs, our tasklets above will not + * be executed any longer. This function then re-enables + * the soft-power switch and allows the user to switch off + * the system. We rely in pdc_soft_power_button_panic() + * since this version spin_trylocks (instead of regular + * spinlock), preventing deadlocks on panic path. */ static int parisc_panic_event(struct notifier_block *this, unsigned long event, void *ptr) { /* re-enable the soft-power switch */ - pdc_soft_power_button(0); + pdc_soft_power_button_panic(0); return NOTIFY_DONE; } @@ -193,7 +197,6 @@ static struct notifier_block parisc_panic_block = { .priority = INT_MAX, }; - static int __init power_init(void) { unsigned long ret; From patchwork Wed Apr 27 22:49:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829685 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25DD4C4332F for ; Wed, 27 Apr 2022 22:55:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238779AbiD0W6K (ORCPT ); Wed, 27 Apr 2022 18:58:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232169AbiD0W5p (ORCPT ); Wed, 27 Apr 2022 18:57:45 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E8258CCF2; Wed, 27 Apr 2022 15:53:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=TyVeNhVW0Rnl3U7SFjjiF4VJ6tQ4RncKJG9ElTcHS+U=; b=hvE2Pj35pHuqn6KDgSKo02+iOD gaZNRqkVbFn9vQ1y4MBHDanrICwEYbseYlrZHBUEFfY68VDZIQ086YHf/rCSUp+hPGKR8FYY9OK9v nYOOhcV6bCO8xGO+p+XNcPdbjxcGSaZZe5jlsSnm9qDCOj58ux/NyJ6hacLVBQ9lf2Np1cQmzz6Ne TKKibQQEw+thoGU6lpUAnc5gpYGmm9vwgSbtaH7Vh06JStgGFCN2k8m/ySu3R2fY0mjZnaQFnJp9F 5MYFwY+RbtGzq1Awmj6tWKuAJuhkis/a6p5VVxSla36X0DRApqZ71nyvJTNmXiYqTaGH5nkcLaKsD z1NFv2eQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqWy-0002D9-Gr; Thu, 28 Apr 2022 00:53:09 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Alexander Gordeev , Christian Borntraeger , Heiko Carstens , Sven Schnelle , Vasily Gorbik Subject: [PATCH 13/30] s390/consoles: Improve panic notifiers reliability Date: Wed, 27 Apr 2022 19:49:07 -0300 Message-Id: <20220427224924.592546-14-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently many console drivers for s390 rely on panic/reboot notifiers to invoke callbacks on these events. The panic() function disables local IRQs, secondary CPUs and preemption, so callbacks invoked on panic are effectively running in atomic context. Happens that most of these console callbacks from s390 doesn't take the proper care with regards to atomic context, like taking spinlocks that might be taken in other function/CPU and hence will cause a lockup situation. The goal for this patch is to improve the notifiers reliability, acting on 4 console drivers, as detailed below: (1) con3215: changed a regular spinlock to the trylock alternative. (2) con3270: also changed a regular spinlock to its trylock counterpart, but here we also have another problem: raw3270_activate_view() takes a different spinlock. So, we worked a helper to validate if this other lock is safe to acquire, and if so, raw3270_activate_view() should be safe. Notice though that there is a functional change here: it's now possible to continue the notifier code [reaching con3270_wait_write() and con3270_rebuild_update()] without executing raw3270_activate_view(). (3) sclp: a global lock is used heavily in the functions called from the notifier, so we added a check here - if the lock is taken already, we just bail-out, preventing the lockup. (4) sclp_vt220: same as (3), a lock validation was added to prevent the potential lockup problem. Besides (1)-(4), we also removed useless void functions, adding the code called from the notifier inside its own body, and changed the priority of such notifiers to execute late, since they are "heavyweight" for the panic environment, so we aim to reduce risks here. Changed return values to NOTIFY_DONE as well, the standard one. Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Heiko Carstens Cc: Sven Schnelle Cc: Vasily Gorbik Signed-off-by: Guilherme G. Piccoli --- As a design choice, the option used here to verify a given spinlock is taken was the function "spin_is_locked()" - but we noticed that it is not often used. An alternative would to take the lock with a spin_trylock() and if it succeeds, just release the spinlock and continue the code. But that seemed weird... Also, we'd like to ask a good validation of case (2) potential functionality change from the s390 console experts - far from expert here, and in our naive code observation, that seems fine, but that analysis might be missing some corner case. Thanks in advance! drivers/s390/char/con3215.c | 36 +++++++++++++++-------------- drivers/s390/char/con3270.c | 34 +++++++++++++++------------ drivers/s390/char/raw3270.c | 18 +++++++++++++++ drivers/s390/char/raw3270.h | 1 + drivers/s390/char/sclp_con.c | 28 +++++++++++++---------- drivers/s390/char/sclp_vt220.c | 42 +++++++++++++++++++--------------- 6 files changed, 96 insertions(+), 63 deletions(-) diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c index f356607835d8..192198bd3dc4 100644 --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -771,35 +771,37 @@ static struct tty_driver *con3215_device(struct console *c, int *index) } /* - * panic() calls con3215_flush through a panic_notifier - * before the system enters a disabled, endless loop. + * The below function is called as a panic/reboot notifier before the + * system enters a disabled, endless loop. + * + * Notice we must use the spin_trylock() alternative, to prevent lockups + * in atomic context (panic routine runs with secondary CPUs, local IRQs + * and preemption disabled). */ -static void con3215_flush(void) -{ - struct raw3215_info *raw; - unsigned long flags; - - raw = raw3215[0]; /* console 3215 is the first one */ - spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags); - raw3215_make_room(raw, RAW3215_BUFFER_SIZE); - spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); -} - static int con3215_notify(struct notifier_block *self, unsigned long event, void *data) { - con3215_flush(); - return NOTIFY_OK; + struct raw3215_info *raw; + unsigned long flags; + + raw = raw3215[0]; /* console 3215 is the first one */ + if (!spin_trylock_irqsave(get_ccwdev_lock(raw->cdev), flags)) + return NOTIFY_DONE; + + raw3215_make_room(raw, RAW3215_BUFFER_SIZE); + spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); + + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = con3215_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = con3215_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; /* diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c index e4592890f20a..476202f3d8a0 100644 --- a/drivers/s390/char/con3270.c +++ b/drivers/s390/char/con3270.c @@ -535,20 +535,29 @@ con3270_wait_write(struct con3270 *cp) } /* - * panic() calls con3270_flush through a panic_notifier - * before the system enters a disabled, endless loop. + * The below function is called as a panic/reboot notifier before the + * system enters a disabled, endless loop. + * + * Notice we must use the spin_trylock() alternative, to prevent lockups + * in atomic context (panic routine runs with secondary CPUs, local IRQs + * and preemption disabled). */ -static void -con3270_flush(void) +static int con3270_notify(struct notifier_block *self, + unsigned long event, void *data) { struct con3270 *cp; unsigned long flags; cp = condev; if (!cp->view.dev) - return; - raw3270_activate_view(&cp->view); - spin_lock_irqsave(&cp->view.lock, flags); + return NOTIFY_DONE; + + if (!raw3270_view_lock_unavailable(&cp->view)) + raw3270_activate_view(&cp->view); + + if (!spin_trylock_irqsave(&cp->view.lock, flags)) + return NOTIFY_DONE; + con3270_wait_write(cp); cp->nr_up = 0; con3270_rebuild_update(cp); @@ -560,23 +569,18 @@ con3270_flush(void) con3270_wait_write(cp); } spin_unlock_irqrestore(&cp->view.lock, flags); -} -static int con3270_notify(struct notifier_block *self, - unsigned long event, void *data) -{ - con3270_flush(); - return NOTIFY_OK; + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = con3270_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = con3270_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; /* diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c index dfde0d941c3c..7b87f9451508 100644 --- a/drivers/s390/char/raw3270.c +++ b/drivers/s390/char/raw3270.c @@ -830,6 +830,24 @@ raw3270_create_device(struct ccw_device *cdev) return rp; } +/* + * This helper just validates that it is safe to activate a + * view in the panic() context, due to locking restrictions. + */ +int +raw3270_view_lock_unavailable(struct raw3270_view *view) +{ + struct raw3270 *rp = view->dev; + + if (!rp) + return -ENODEV; + + if (spin_is_locked(get_ccwdev_lock(rp->cdev))) + return -EBUSY; + + return 0; +} + /* * Activate a view. */ diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h index c6645167cd2b..4cb6b5ee44ca 100644 --- a/drivers/s390/char/raw3270.h +++ b/drivers/s390/char/raw3270.h @@ -160,6 +160,7 @@ struct raw3270_view { }; int raw3270_add_view(struct raw3270_view *, struct raw3270_fn *, int, int); +int raw3270_view_lock_unavailable(struct raw3270_view *view); int raw3270_activate_view(struct raw3270_view *); void raw3270_del_view(struct raw3270_view *); void raw3270_deactivate_view(struct raw3270_view *); diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index fe5ee2646fcf..e5d947c763ea 100644 --- a/drivers/s390/char/sclp_con.c +++ b/drivers/s390/char/sclp_con.c @@ -220,30 +220,34 @@ sclp_console_device(struct console *c, int *index) } /* - * Make sure that all buffers will be flushed to the SCLP. + * This panic/reboot notifier makes sure that all buffers + * will be flushed to the SCLP. */ -static void -sclp_console_flush(void) -{ - sclp_conbuf_emit(); - sclp_console_sync_queue(); -} - static int sclp_console_notify(struct notifier_block *self, unsigned long event, void *data) { - sclp_console_flush(); - return NOTIFY_OK; + /* + * Perform the lock check before effectively getting the + * lock on sclp_conbuf_emit() / sclp_console_sync_queue() + * to prevent potential lockups in atomic context. + */ + if (spin_is_locked(&sclp_con_lock)) + return NOTIFY_DONE; + + sclp_conbuf_emit(); + sclp_console_sync_queue(); + + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = sclp_console_notify, - .priority = 1, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = sclp_console_notify, - .priority = 1, + .priority = INT_MIN + 1, /* run the callback late */ }; /* diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index 3b4e7e5d9b71..a32f34a1c6d2 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -769,21 +769,6 @@ __initcall(sclp_vt220_tty_init); #ifdef CONFIG_SCLP_VT220_CONSOLE -static void __sclp_vt220_flush_buffer(void) -{ - unsigned long flags; - - sclp_vt220_emit_current(); - spin_lock_irqsave(&sclp_vt220_lock, flags); - del_timer(&sclp_vt220_timer); - while (sclp_vt220_queue_running) { - spin_unlock_irqrestore(&sclp_vt220_lock, flags); - sclp_sync_wait(); - spin_lock_irqsave(&sclp_vt220_lock, flags); - } - spin_unlock_irqrestore(&sclp_vt220_lock, flags); -} - static void sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count) { @@ -797,22 +782,41 @@ sclp_vt220_con_device(struct console *c, int *index) return sclp_vt220_driver; } +/* + * This panic/reboot notifier runs in atomic context, so + * locking restrictions apply to prevent potential lockups. + */ static int sclp_vt220_notify(struct notifier_block *self, unsigned long event, void *data) { - __sclp_vt220_flush_buffer(); - return NOTIFY_OK; + unsigned long flags; + + if (spin_is_locked(&sclp_vt220_lock)) + return NOTIFY_DONE; + + sclp_vt220_emit_current(); + + spin_lock_irqsave(&sclp_vt220_lock, flags); + del_timer(&sclp_vt220_timer); + while (sclp_vt220_queue_running) { + spin_unlock_irqrestore(&sclp_vt220_lock, flags); + sclp_sync_wait(); + spin_lock_irqsave(&sclp_vt220_lock, flags); + } + spin_unlock_irqrestore(&sclp_vt220_lock, flags); + + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = sclp_vt220_notify, - .priority = 1, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = sclp_vt220_notify, - .priority = 1, + .priority = INT_MIN + 1, /* run the callback late */ }; /* Structure needed to register with printk */ From patchwork Wed Apr 27 22:49:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829686 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58B39C4332F for ; Wed, 27 Apr 2022 22:55:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238615AbiD0W6X (ORCPT ); Wed, 27 Apr 2022 18:58:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239159AbiD0W5t (ORCPT ); Wed, 27 Apr 2022 18:57:49 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B6558CCFB; Wed, 27 Apr 2022 15:53:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=mOzFWStqo1l1SFAwioSEW9cov+DtDc5WSMbZaYL5OFk=; b=jORyziNh7Mp7CJnb2ldBvIVUYT miqK/KwxTCDE0PrnGOVoO5V4xtjW+TEXZOKHxzyxZAzEuCslLE//gxMpeQbei+ydr8zg3pnWZUWxE L40pn68w+NUbAHLuqvLt2UI0hgcbpQZODu83KlzMI8qRKWoyX30oYob/b9pQLrf+6HFREi99ePbwb zW4TblodvYrIgJCYkkWUlwk3Cl/V3uSBOUWLD/GIZmkaB62kyu6wuslAaH0LxO2Qqyrw8rvwJQSXp vohmbyikfHUVSRBgOx4Bv9HUeJbAvmB/X4rw1kDURxjWp8eCgUztnLBZm1GN+7lilt+TPvGD7Gymp FQwd7uqA==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqXD-0002EK-E5; Thu, 28 Apr 2022 00:53:24 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 14/30] panic: Properly identify the panic event to the notifiers' callbacks Date: Wed, 27 Apr 2022 19:49:08 -0300 Message-Id: <20220427224924.592546-15-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The notifiers infrastructure provides a way to pass an "id" to the callbacks to determine what kind of event happened, i.e., what is the reason behind they getting called. The panic notifier currently pass 0, but this is soon to be used in a multi-targeted notifier, so let's pass a meaningful "id" over there. Signed-off-by: Guilherme G. Piccoli --- include/linux/panic_notifier.h | 5 +++++ kernel/panic.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 41e32483d7a7..07dced83a783 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -9,4 +9,9 @@ extern struct atomic_notifier_head panic_notifier_list; extern bool crash_kexec_post_notifiers; +enum panic_notifier_val { + PANIC_UNUSED, + PANIC_NOTIFIER = 0xDEAD, +}; + #endif /* _LINUX_PANIC_NOTIFIERS_H */ diff --git a/kernel/panic.c b/kernel/panic.c index eb4dfb932c85..523bc9ccd0e9 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -287,7 +287,7 @@ void panic(const char *fmt, ...) * Run any panic handlers, including those that might need to * add information to the kmsg dump output. */ - atomic_notifier_call_chain(&panic_notifier_list, 0, buf); + atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf); panic_print_sys_info(false); From patchwork Wed Apr 27 22:49:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829689 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62996C4321E for ; Wed, 27 Apr 2022 22:56:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239209AbiD0W76 (ORCPT ); Wed, 27 Apr 2022 18:59:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239398AbiD0W5x (ORCPT ); Wed, 27 Apr 2022 18:57:53 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 433568D69A; Wed, 27 Apr 2022 15:53:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=LH6oQ+KUrT2+UZ27jtgU/PGKhQQ202wn79cJAeqj5IE=; b=N1tY0S0aaQeR9NcKuaJbTqnNXy 9pcqa1SEZnYDO5/TLstJB48aWkEQ4PDoBYIETAyDlKfJL300Z2BuvN4dT08YXOJQkKQRfd88YbBla BhKcNiLHKco0hFkhYWPs6DIH4v+5YaEldHsDLnnpsbsgJuChEIxNDXB5/EzphACOoX7xqZH0abztl vLKxKzrcWguRmMXDmvcU5nsznWqZJ1nSmpm/gOBpgQqBxhdFVL/WA1XIODSmEAnbcKKqL8Xui+5p0 wYd62C0elRAkgaFmQPZ2Uk5W3nR2kjl80X0bqLIyvZBOzCHJbiVCOEqqyvgKj3yUn8TPr60YsbPp0 Lml85pLA==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqXT-0002FK-Kn; Thu, 28 Apr 2022 00:53:40 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Brian Norris , Florian Fainelli Subject: [PATCH 15/30] bus: brcmstb_gisb: Clean-up panic/die notifiers Date: Wed, 27 Apr 2022 19:49:09 -0300 Message-Id: <20220427224924.592546-16-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org This patch improves the panic/die notifiers in this driver by making use of a passed "id" instead of comparing pointer address; also, it removes an useless prototype declaration and unnecessary header inclusion. This is part of a panic notifiers refactor - this notifier in the future will be moved to a new list, that encompass the information notifiers only. Fixes: 9eb60880d9a9 ("bus: brcmstb_gisb: add notifier handling") Cc: Brian Norris Cc: Florian Fainelli Signed-off-by: Guilherme G. Piccoli Acked-by: Florian Fainelli --- drivers/bus/brcmstb_gisb.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c index 183d5cc37d42..1ea7b015e225 100644 --- a/drivers/bus/brcmstb_gisb.c +++ b/drivers/bus/brcmstb_gisb.c @@ -19,7 +19,6 @@ #include #include #include -#include #ifdef CONFIG_MIPS #include @@ -347,25 +346,14 @@ static irqreturn_t brcmstb_gisb_bp_handler(int irq, void *dev_id) /* * Dump out gisb errors on die or panic. */ -static int dump_gisb_error(struct notifier_block *self, unsigned long v, - void *p); - -static struct notifier_block gisb_die_notifier = { - .notifier_call = dump_gisb_error, -}; - -static struct notifier_block gisb_panic_notifier = { - .notifier_call = dump_gisb_error, -}; - static int dump_gisb_error(struct notifier_block *self, unsigned long v, void *p) { struct brcmstb_gisb_arb_device *gdev; - const char *reason = "panic"; + const char *reason = "die"; - if (self == &gisb_die_notifier) - reason = "die"; + if (v == PANIC_NOTIFIER) + reason = "panic"; /* iterate over each GISB arb registered handlers */ list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next) @@ -374,6 +362,14 @@ static int dump_gisb_error(struct notifier_block *self, unsigned long v, return NOTIFY_DONE; } +static struct notifier_block gisb_die_notifier = { + .notifier_call = dump_gisb_error, +}; + +static struct notifier_block gisb_panic_notifier = { + .notifier_call = dump_gisb_error, +}; + static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO, gisb_arb_get_timeout, gisb_arb_set_timeout); From patchwork Wed Apr 27 22:49:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829692 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1529CC4332F for ; Wed, 27 Apr 2022 22:56:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239268AbiD0W77 (ORCPT ); Wed, 27 Apr 2022 18:59:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239616AbiD0W6L (ORCPT ); Wed, 27 Apr 2022 18:58:11 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2ABF8E1A4; Wed, 27 Apr 2022 15:54:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=jr6PPJ/atoVQEyGdnH+YsU0AoovP8gRpIrvldNTpl+c=; b=ZaESizBX6Rvr+B8MTwj+F1hsx0 TWMp+gf9Io6e1FsR2UKJOjzbHs6qLm52XlDnoXO+RzNMu3SkomKypU9iwkVaK5Bqa7ShVw0pw00Kp fujm/8kyfH6iuIIDam6L6uEqfdWPgiVKAJ9VFDPPEEOuP114yBIfNVKo+BdDMswd4oQFFBy0f1ZLI mTRoQaTdP5jbR2QiHo9Su/NVNzsL7BHWKl9w6IpBA0zzwN/TL+4rwH7vQNft8J1AAGTDlFILy+oXN 3VHdSwGj5OvLrvgNSuTRoQEPOGiiV4mpG60XBb4y5x9eVCckUZfRP0lJtx7j5o67sNcEn6v23HcoW LqvtZDZQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqXh-0002GB-Ux; Thu, 28 Apr 2022 00:53:54 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Andrea Parri , Dexuan Cui , Haiyang Zhang , "K. Y. Srinivasan" , Stephen Hemminger , Tianyu Lan , Wei Liu Subject: [PATCH 16/30] drivers/hv/vmbus, video/hyperv_fb: Untangle and refactor Hyper-V panic notifiers Date: Wed, 27 Apr 2022 19:49:10 -0300 Message-Id: <20220427224924.592546-17-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently Hyper-V guests are among the most relevant users of the panic infrastructure, like panic notifiers, kmsg dumpers, etc. The reasons rely both in cleaning-up procedures (closing a hypervisor <-> guest connection, disabling a paravirtualized timer) as well as to data collection (sending panic information to the hypervisor) and framebuffer management. The thing is: some notifiers are related to others, ordering matters, some functionalities are duplicated and there are lots of conditionals behind sending panic information to the hypervisor. This patch, as part of an effort to clean-up the panic notifiers mechanism and better document things, address some of the issues/complexities of Hyper-V panic handling through the following changes: (a) We have die and panic notifiers on vmbus_drv.c and both have goals of sending panic information to the hypervisor, though the panic notifier is also responsible for a cleaning-up procedure. This commit clears the code by splitting the panic notifier in two, one for closing the vmbus connection whereas the other is only for sending panic info to hypervisor. With that, it was possible to merge the die and panic notifiers in a single/well-documented function, and clear some conditional complexities on sending such information to the hypervisor. (b) The new panic notifier created after (a) is only doing a single thing: cleaning the vmbus connection. This procedure might cause a delay (due to hypervisor I/O completion), so we postpone that to run late. But more relevant: this *same* vmbus unloading happens in the crash_shutdown() handler, so if kdump is set, we can safely skip this panic notifier and defer such clean-up to the kexec crash handler. (c) There is also a Hyper-V framebuffer panic notifier, which relies in doing a vmbus operation that demands a valid connection. So, we must order this notifier with the panic notifier from vmbus_drv.c, in order to guarantee that the framebuffer code executes before the vmbus connection is unloaded. Also, this commit removes a useless header. Although there is code rework and re-ordering, we expect that this change has no functional regressions but instead optimize the path and increase panic reliability on Hyper-V. This was tested on Hyper-V with success. Fixes: 792f232d57ff ("Drivers: hv: vmbus: Fix potential crash on module unload") Fixes: 74347a99e73a ("x86/Hyper-V: Unload vmbus channel in hv panic callback") Cc: Andrea Parri (Microsoft) Cc: Dexuan Cui Cc: Haiyang Zhang Cc: "K. Y. Srinivasan" Cc: Michael Kelley Cc: Stephen Hemminger Cc: Tianyu Lan Cc: Wei Liu Tested-by: Fabio A M Martins Signed-off-by: Guilherme G. Piccoli --- Special thanks to Michael Kelley for the good information about the Hyper-V panic path in email threads some months ago, and to Fabio for the testing performed. Michael and all Microsoft folks: a careful analysis to double-check our changes and assumptions here is really appreciated, this code is complex and intricate, it is possible some corner case might have been overlooked. Thanks in advance! drivers/hv/vmbus_drv.c | 109 ++++++++++++++++++++------------ drivers/video/fbdev/hyperv_fb.c | 8 +++ 2 files changed, 76 insertions(+), 41 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 14de17087864..f37f12d48001 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -24,11 +24,11 @@ #include #include -#include #include #include #include #include +#include #include #include #include @@ -68,51 +68,75 @@ static int hyperv_report_reg(void) return !sysctl_record_panic_msg || !hv_panic_page; } -static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, +/* + * The panic notifier below is responsible solely for unloading the + * vmbus connection, which is necessary in a panic event. But notice + * that this same unloading procedure is executed in the Hyper-V + * crash_shutdown() handler [see hv_crash_handler()], which basically + * means that we can postpone its execution if we have kdump set, + * since it will run the crash_shutdown() handler anyway. Even more + * intrincated is the relation of this notifier with Hyper-V framebuffer + * panic notifier - we need vmbus connection alive there in order to + * succeed, so we need to order both with each other [for reference see + * hvfb_on_panic()] - this is done using notifiers' priorities. + */ +static int hv_panic_vmbus_unload(struct notifier_block *nb, unsigned long val, void *args) +{ + if (!kexec_crash_loaded()) + vmbus_initiate_unload(true); + + return NOTIFY_DONE; +} +static struct notifier_block hyperv_panic_vmbus_unload_block = { + .notifier_call = hv_panic_vmbus_unload, + .priority = INT_MIN + 1, /* almost the latest one to execute */ +}; + +/* + * The following callback works both as die and panic notifier; its + * goal is to provide panic information to the hypervisor unless the + * kmsg dumper is gonna be used [see hv_kmsg_dump()], which provides + * more information but is not always available. + * + * Notice that both the panic/die report notifiers are registered only + * if we have the capability HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE set. + */ +static int hv_die_panic_notify_crash(struct notifier_block *nb, + unsigned long val, void *args) { struct pt_regs *regs; + bool is_die; - vmbus_initiate_unload(true); - - /* - * Hyper-V should be notified only once about a panic. If we will be - * doing hv_kmsg_dump() with kmsg data later, don't do the notification - * here. - */ - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE - && hyperv_report_reg()) { + /* Don't notify Hyper-V unless we have a die oops event or panic. */ + switch (val) { + case DIE_OOPS: + is_die = true; + regs = ((struct die_args *)args)->regs; + break; + case PANIC_NOTIFIER: + is_die = false; regs = current_pt_regs(); - hyperv_report_panic(regs, val, false); - } - return NOTIFY_DONE; -} - -static int hyperv_die_event(struct notifier_block *nb, unsigned long val, - void *args) -{ - struct die_args *die = args; - struct pt_regs *regs = die->regs; - - /* Don't notify Hyper-V if the die event is other than oops */ - if (val != DIE_OOPS) + break; + default: return NOTIFY_DONE; + } /* - * Hyper-V should be notified only once about a panic. If we will be - * doing hv_kmsg_dump() with kmsg data later, don't do the notification - * here. + * Hyper-V should be notified only once about a panic/die. If we will + * be calling hv_kmsg_dump() later with kmsg data, don't do the + * notification here. */ if (hyperv_report_reg()) - hyperv_report_panic(regs, val, true); + hyperv_report_panic(regs, val, is_die); + return NOTIFY_DONE; } - -static struct notifier_block hyperv_die_block = { - .notifier_call = hyperv_die_event, +static struct notifier_block hyperv_die_report_block = { + .notifier_call = hv_die_panic_notify_crash, }; -static struct notifier_block hyperv_panic_block = { - .notifier_call = hyperv_panic_event, +static struct notifier_block hyperv_panic_report_block = { + .notifier_call = hv_die_panic_notify_crash, }; static const char *fb_mmio_name = "fb_range"; @@ -1589,16 +1613,17 @@ static int vmbus_bus_init(void) if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG) hv_kmsg_dump_register(); - register_die_notifier(&hyperv_die_block); + register_die_notifier(&hyperv_die_report_block); + atomic_notifier_chain_register(&panic_notifier_list, + &hyperv_panic_report_block); } /* - * Always register the panic notifier because we need to unload - * the VMbus channel connection to prevent any VMbus - * activity after the VM panics. + * Always register the vmbus unload panic notifier because we + * need to shut the VMbus channel connection on panic. */ atomic_notifier_chain_register(&panic_notifier_list, - &hyperv_panic_block); + &hyperv_panic_vmbus_unload_block); vmbus_request_offers(); @@ -2817,15 +2842,17 @@ static void __exit vmbus_exit(void) if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { kmsg_dump_unregister(&hv_kmsg_dumper); - unregister_die_notifier(&hyperv_die_block); + unregister_die_notifier(&hyperv_die_report_block); + atomic_notifier_chain_unregister(&panic_notifier_list, + &hyperv_panic_report_block); } /* - * The panic notifier is always registered, hence we should + * The vmbus panic notifier is always registered, hence we should * also unconditionally unregister it here as well. */ atomic_notifier_chain_unregister(&panic_notifier_list, - &hyperv_panic_block); + &hyperv_panic_vmbus_unload_block); free_page((unsigned long)hv_panic_page); unregister_sysctl_table(hv_ctl_table_hdr); diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c index c8e0ea27caf1..f3494b868a64 100644 --- a/drivers/video/fbdev/hyperv_fb.c +++ b/drivers/video/fbdev/hyperv_fb.c @@ -1244,7 +1244,15 @@ static int hvfb_probe(struct hv_device *hdev, par->fb_ready = true; par->synchronous_fb = false; + + /* + * We need to be sure this panic notifier runs _before_ the + * vmbus disconnect, so order it by priority. It must execute + * before the function hv_panic_vmbus_unload() [drivers/hv/vmbus_drv.c], + * which is almost at the end of list, with priority = INT_MIN + 1. + */ par->hvfb_panic_nb.notifier_call = hvfb_on_panic; + par->hvfb_panic_nb.priority = INT_MIN + 10, atomic_notifier_chain_register(&panic_notifier_list, &par->hvfb_panic_nb); From patchwork Wed Apr 27 22:49:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829688 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DBB0C4332F for ; Wed, 27 Apr 2022 22:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238601AbiD0W7z (ORCPT ); Wed, 27 Apr 2022 18:59:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239738AbiD0W7D (ORCPT ); Wed, 27 Apr 2022 18:59:03 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B959390CEB; Wed, 27 Apr 2022 15:54:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=gwBR7P38mmxeEI4wWnwfuOo3Vx6Wo8buxtIoJ+/ueVE=; b=nwXMrZImrRof6aT4nflSriZWm8 nV+2kfTnZMr3qMfu/pdKx8zdoFC6dPSZfgjMR8nrCqKQx0a9STr9zXRmf603LSCMYxoe/0rzj8WAX X04mzyflhbAneN3N3eqd1bEuJEgnFV2TubG1LTS2zdwee0DTxDCCfkp/jZLLefrxcRie9zAR6UkMF CbBI0mU22IJBGJ0ER3H7bHP1OaQk7bRcIVlpHROO0rfL6uLx6VUv9a0aPf+94uNbhp5w7FYgnWnfd FC3cJ2sUp+UEhn1teUMFvXk88fY0u++AP/ytEp5+rJzALI+oR2Quq3NLCvwKLKxi/cwHyaoyY3uHg LhfKC/tQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqY1-0002Ha-Aa; Thu, 28 Apr 2022 00:54:15 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 17/30] tracing: Improve panic/die notifiers Date: Wed, 27 Apr 2022 19:49:11 -0300 Message-Id: <20220427224924.592546-18-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the tracing dump_on_oops feature is implemented through separate notifiers, one for die/oops and the other for panic. With the addition of panic notifier "id", this patch makes use of such "id" to unify both functions. It also comments the function and changes the priority of the notifier blocks, in order they run early compared to other notifiers, to prevent useless trace data (like the callback names for the other notifiers). Finally, we also removed an unnecessary header inclusion. Signed-off-by: Guilherme G. Piccoli Acked-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 57 +++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 25 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f4de111fa18f..c1d8a3622ccc 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -19,7 +19,6 @@ #include #include #include -#include #include #include #include @@ -9767,38 +9766,46 @@ static __init int tracer_init_tracefs(void) fs_initcall(tracer_init_tracefs); -static int trace_panic_handler(struct notifier_block *this, - unsigned long event, void *unused) +/* + * The idea is to execute the following die/panic callback early, in order + * to avoid showing irrelevant information in the trace (like other panic + * notifier functions); we are the 2nd to run, after hung_task/rcu_stall + * warnings get disabled (to prevent potential log flooding). + */ +static int trace_die_panic_handler(struct notifier_block *self, + unsigned long ev, void *unused) { - if (ftrace_dump_on_oops) + int do_dump; + + if (!ftrace_dump_on_oops) + return NOTIFY_DONE; + + switch (ev) { + case DIE_OOPS: + do_dump = 1; + break; + case PANIC_NOTIFIER: + do_dump = 1; + break; + default: + do_dump = 0; + break; + } + + if (do_dump) ftrace_dump(ftrace_dump_on_oops); - return NOTIFY_OK; + + return NOTIFY_DONE; } static struct notifier_block trace_panic_notifier = { - .notifier_call = trace_panic_handler, - .next = NULL, - .priority = 150 /* priority: INT_MAX >= x >= 0 */ + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, }; -static int trace_die_handler(struct notifier_block *self, - unsigned long val, - void *data) -{ - switch (val) { - case DIE_OOPS: - if (ftrace_dump_on_oops) - ftrace_dump(ftrace_dump_on_oops); - break; - default: - break; - } - return NOTIFY_OK; -} - static struct notifier_block trace_die_notifier = { - .notifier_call = trace_die_handler, - .priority = 200 + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, }; /* From patchwork Wed Apr 27 22:49:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829691 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A01BBC433F5 for ; Wed, 27 Apr 2022 22:56:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239256AbiD0W76 (ORCPT ); Wed, 27 Apr 2022 18:59:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239774AbiD0W7F (ORCPT ); Wed, 27 Apr 2022 18:59:05 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9360F8C7C7; Wed, 27 Apr 2022 15:54:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=oI9b5duO8OJ5vQDZCcg8/YSfwN8M5sfdHxH8XUnmtlk=; b=Dl2B7pSVJp25fe7IfIs24mmkq8 hNWQZdfuE5b8NzwyHqbjR/6C1jbxbEv8wNNcNdcZK+x2mWiNzNr+u6ej0RkZPoYhNEHBCsZ6UD+6G UKVT1x0W1ctGqUC1Gq0pKfbBSIn3/AQDQpBwhuyH0wupCzlBVEy+S+oaSi7mTGACgenSYzi35Memm cwNrE6VLPhA8HIa6SL7ijwVZV/Cmf5guYFGY1etNEWb16ALz0OIjrK84zUZZaRulPOC47prAFsrmC 8jtFSnfk5SwoqCho0RbgOB8YFry+V3AQ6FT8GxIeK9uuEGFeYv+qjRy2g8pgwIU4Wj4/dnNONMvQE 5U+RG0NQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqYG-0002IR-Ki; Thu, 28 Apr 2022 00:54:29 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Arjan van de Ven , Cong Wang , Sebastian Andrzej Siewior , Valentin Schneider , Xiaoming Ni Subject: [PATCH 18/30] notifier: Show function names on notifier routines if DEBUG_NOTIFIERS is set Date: Wed, 27 Apr 2022 19:49:12 -0300 Message-Id: <20220427224924.592546-19-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently we have a debug infrastructure in the notifiers file, but it's very simple/limited. This patch extends it by: (a) Showing all registered/unregistered notifiers' callback names; (b) Adding a dynamic debug tuning to allow showing called notifiers' function names. Notice that this should be guarded as a tunable since it can flood the kernel log buffer. Cc: Arjan van de Ven Cc: Cong Wang Cc: Sebastian Andrzej Siewior Cc: Valentin Schneider Cc: Xiaoming Ni Signed-off-by: Guilherme G. Piccoli --- We have some design decisions that worth discussing here: (a) First of call, using C99 helps a lot to write clear and concise code, but due to commit 4d94f910e79a ("Kbuild: use -Wdeclaration-after-statement") we have a warning if mixing variable declarations with code. For this patch though, doing that makes the code way clear, so decision was to add the debug code inside brackets whenever this warning pops up. We can change that, but that'll cause more ifdefs in the same function. (b) In the symbol lookup helper function, we modify the parameter passed but even more, we return it as well! This is unusual and seems unnecessary, but was the strategy taken to allow embedding such function in the pr_debug() call. Not doing that would likely requiring 3 symbol_name variables to avoid concurrency (registering notifier A while calling notifier B) - we rely in local variables as a serialization mechanism. We're open for suggestions in case this design is not appropriate; thanks in advance! kernel/notifier.c | 48 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) diff --git a/kernel/notifier.c b/kernel/notifier.c index ba005ebf4730..21032ebcde57 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -7,6 +7,22 @@ #include #include +#ifdef CONFIG_DEBUG_NOTIFIERS +#include + +/* + * Helper to get symbol names in case DEBUG_NOTIFIERS is set. + * Return the modified parameter is a strategy used to achieve + * the pr_debug() functionality - with this, function is only + * executed if the dynamic debug tuning is effectively set. + */ +static inline char *notifier_name(struct notifier_block *nb, char *sym_name) +{ + lookup_symbol_name((unsigned long)(nb->notifier_call), sym_name); + return sym_name; +} +#endif + /* * Notifier list for kernel code which wants to be called * at shutdown. This is used to stop any idling DMA operations @@ -34,20 +50,41 @@ static int notifier_chain_register(struct notifier_block **nl, } n->next = *nl; rcu_assign_pointer(*nl, n); + +#ifdef CONFIG_DEBUG_NOTIFIERS + { + char sym_name[KSYM_NAME_LEN]; + + pr_info("notifiers: registered %s()\n", + notifier_name(n, sym_name)); + } +#endif return 0; } static int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) { + int ret = -ENOENT; + while ((*nl) != NULL) { if ((*nl) == n) { rcu_assign_pointer(*nl, n->next); - return 0; + ret = 0; + break; } nl = &((*nl)->next); } - return -ENOENT; + +#ifdef CONFIG_DEBUG_NOTIFIERS + if (!ret) { + char sym_name[KSYM_NAME_LEN]; + + pr_info("notifiers: unregistered %s()\n", + notifier_name(n, sym_name)); + } +#endif + return ret; } /** @@ -80,6 +117,13 @@ static int notifier_call_chain(struct notifier_block **nl, nb = next_nb; continue; } + + { + char sym_name[KSYM_NAME_LEN]; + + pr_debug("notifiers: calling %s()\n", + notifier_name(nb, sym_name)); + } #endif ret = nb->notifier_call(nb, val, v); From patchwork Wed Apr 27 22:49:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829693 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49D2DC4321E for ; Wed, 27 Apr 2022 22:57:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239312AbiD0XAI (ORCPT ); Wed, 27 Apr 2022 19:00:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240061AbiD0W7J (ORCPT ); Wed, 27 Apr 2022 18:59:09 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D119B368D; Wed, 27 Apr 2022 15:54:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=UhhPFJqW26A1a6soa6rznnjXRjwvDkXyweuhXfNQOVY=; b=MKBh56UTZ7JCBvBjxeK61V4jDM v7kwzQJKazlMRxSRc2ZqArefnMuAMvJRSN0Dm/n3rUqjfn87xJdCwCNZgYYInNcW7KLaZieSBQ8O6 XsgLVHkw+gGyoqVfpHoR7HGpc4dRel8YFV0PNkyLnVjOtFb6zpg44r32e+Cy7IowfRZ1AwUGXIuJK ogEnepSyse/P/gSxYI2obKAoqpGM2oj0KXhOmKybDbZdIj++zZDEM0H4AKnIRoCEV72z/ad5u+yfX mziNZTi1DoyU2ltDkam4BhJMX4t8MGH4SNKViSUOE5Td2/P7EGuXXRrbm7W62coqKt68Zw2u7NGpT +e52kJVw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqYb-0002JS-Nh; Thu, 28 Apr 2022 00:54:50 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Alexander Gordeev , Andrea Parri , Ard Biesheuvel , Benjamin Herrenschmidt , Brian Norris , Christian Borntraeger , Christophe JAILLET , David Gow , "David S. Miller" , Dexuan Cui , Doug Berger , Evan Green , Florian Fainelli , Haiyang Zhang , Hari Bathini , Heiko Carstens , Julius Werner , Justin Chen , "K. Y. Srinivasan" , Lee Jones , Markus Mayer , Michael Ellerman , Mihai Carabas , Nicholas Piggin , Paul Mackerras , Pavel Machek , Scott Branden , Sebastian Reichel , Shile Zhang , Stephen Hemminger , Sven Schnelle , Thomas Bogendoerfer , Tianyu Lan , Vasily Gorbik , Wang ShaoBo , Wei Liu , zhenwei pi Subject: [PATCH 19/30] panic: Add the panic hypervisor notifier list Date: Wed, 27 Apr 2022 19:49:13 -0300 Message-Id: <20220427224924.592546-20-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The goal of this new panic notifier is to allow its users to register callbacks to run very early in the panic path. This aims hypervisor/FW notification mechanisms as well as simple LED functions, and any other simple and safe mechanism that should run early in the panic path; more dangerous callbacks should execute later. For now, the patch is almost a no-op (although it changes a bit the ordering in which some panic notifiers are executed). In a subsequent patch, the panic path will be refactored, then the panic hypervisor notifiers will effectively run very early in the panic path. We also defer documenting it all properly in the subsequent refactor patch. While at it, we removed some useless header inclusions and fixed some notifiers return too (by using the standard NOTIFY_DONE). Cc: Alexander Gordeev Cc: Andrea Parri (Microsoft) Cc: Ard Biesheuvel Cc: Benjamin Herrenschmidt Cc: Brian Norris Cc: Christian Borntraeger Cc: Christophe JAILLET Cc: David Gow Cc: "David S. Miller" Cc: Dexuan Cui Cc: Doug Berger Cc: Evan Green Cc: Florian Fainelli Cc: Haiyang Zhang Cc: Hari Bathini Cc: Heiko Carstens Cc: Julius Werner Cc: Justin Chen Cc: "K. Y. Srinivasan" Cc: Lee Jones Cc: Markus Mayer Cc: Michael Ellerman Cc: Michael Kelley Cc: Mihai Carabas Cc: Nicholas Piggin Cc: Paul Mackerras Cc: Pavel Machek Cc: Scott Branden Cc: Sebastian Reichel Cc: Shile Zhang Cc: Stephen Hemminger Cc: Sven Schnelle Cc: Thomas Bogendoerfer Cc: Tianyu Lan Cc: Vasily Gorbik Cc: Wang ShaoBo Cc: Wei Liu Cc: zhenwei pi Signed-off-by: Guilherme G. Piccoli --- arch/mips/sgi-ip22/ip22-reset.c | 2 +- arch/mips/sgi-ip32/ip32-reset.c | 3 +-- arch/powerpc/kernel/setup-common.c | 2 +- arch/sparc/kernel/sstate.c | 3 +-- drivers/firmware/google/gsmi.c | 4 ++-- drivers/hv/vmbus_drv.c | 4 ++-- drivers/leds/trigger/ledtrig-activity.c | 4 ++-- drivers/leds/trigger/ledtrig-heartbeat.c | 4 ++-- drivers/misc/bcm-vk/bcm_vk_dev.c | 6 +++--- drivers/misc/pvpanic/pvpanic.c | 4 ++-- drivers/power/reset/ltc2952-poweroff.c | 4 ++-- drivers/s390/char/zcore.c | 5 +++-- drivers/soc/bcm/brcmstb/pm/pm-arm.c | 2 +- include/linux/panic_notifier.h | 1 + kernel/panic.c | 4 ++++ 15 files changed, 28 insertions(+), 24 deletions(-) diff --git a/arch/mips/sgi-ip22/ip22-reset.c b/arch/mips/sgi-ip22/ip22-reset.c index 8f0861c58080..3023848acbf1 100644 --- a/arch/mips/sgi-ip22/ip22-reset.c +++ b/arch/mips/sgi-ip22/ip22-reset.c @@ -195,7 +195,7 @@ static int __init reboot_setup(void) } timer_setup(&blink_timer, blink_timeout, 0); - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); + atomic_notifier_chain_register(&panic_hypervisor_list, &panic_block); return 0; } diff --git a/arch/mips/sgi-ip32/ip32-reset.c b/arch/mips/sgi-ip32/ip32-reset.c index 18d1c115cd53..9ee1302c9d13 100644 --- a/arch/mips/sgi-ip32/ip32-reset.c +++ b/arch/mips/sgi-ip32/ip32-reset.c @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -145,7 +144,7 @@ static __init int ip32_reboot_setup(void) pm_power_off = ip32_machine_halt; timer_setup(&blink_timer, blink_timeout, 0); - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); + atomic_notifier_chain_register(&panic_hypervisor_list, &panic_block); return 0; } diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 52f96b209a96..1468c3937bf4 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -753,7 +753,7 @@ static struct notifier_block ppc_panic_block = { void __init setup_panic(void) { /* Hard-disables IRQs + deal with FW-assisted dump (fadump) */ - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &ppc_fadump_block); if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) diff --git a/arch/sparc/kernel/sstate.c b/arch/sparc/kernel/sstate.c index 3bcc4ddc6911..82b7b68e0bdc 100644 --- a/arch/sparc/kernel/sstate.c +++ b/arch/sparc/kernel/sstate.c @@ -5,7 +5,6 @@ */ #include -#include #include #include #include @@ -106,7 +105,7 @@ static int __init sstate_init(void) do_set_sstate(HV_SOFT_STATE_TRANSITION, booting_msg); - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &sstate_panic_block); register_reboot_notifier(&sstate_reboot_notifier); diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c index b01ed02e4a87..ff0bebe2f444 100644 --- a/drivers/firmware/google/gsmi.c +++ b/drivers/firmware/google/gsmi.c @@ -1034,7 +1034,7 @@ static __init int gsmi_init(void) register_reboot_notifier(&gsmi_reboot_notifier); register_die_notifier(&gsmi_die_notifier); - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &gsmi_panic_notifier); printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n"); @@ -1061,7 +1061,7 @@ static void __exit gsmi_exit(void) { unregister_reboot_notifier(&gsmi_reboot_notifier); unregister_die_notifier(&gsmi_die_notifier); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &gsmi_panic_notifier); #ifdef CONFIG_EFI efivars_unregister(&efivars); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index f37f12d48001..901b97034308 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1614,7 +1614,7 @@ static int vmbus_bus_init(void) hv_kmsg_dump_register(); register_die_notifier(&hyperv_die_report_block); - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &hyperv_panic_report_block); } @@ -2843,7 +2843,7 @@ static void __exit vmbus_exit(void) if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { kmsg_dump_unregister(&hv_kmsg_dumper); unregister_die_notifier(&hyperv_die_report_block); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &hyperv_panic_report_block); } diff --git a/drivers/leds/trigger/ledtrig-activity.c b/drivers/leds/trigger/ledtrig-activity.c index 30bc9df03636..bbbcf3bc17e3 100644 --- a/drivers/leds/trigger/ledtrig-activity.c +++ b/drivers/leds/trigger/ledtrig-activity.c @@ -247,7 +247,7 @@ static int __init activity_init(void) int rc = led_trigger_register(&activity_led_trigger); if (!rc) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &activity_panic_nb); register_reboot_notifier(&activity_reboot_nb); } @@ -257,7 +257,7 @@ static int __init activity_init(void) static void __exit activity_exit(void) { unregister_reboot_notifier(&activity_reboot_nb); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &activity_panic_nb); led_trigger_unregister(&activity_led_trigger); } diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c index 7fe0a05574d2..a1ed25e83c8f 100644 --- a/drivers/leds/trigger/ledtrig-heartbeat.c +++ b/drivers/leds/trigger/ledtrig-heartbeat.c @@ -190,7 +190,7 @@ static int __init heartbeat_trig_init(void) int rc = led_trigger_register(&heartbeat_led_trigger); if (!rc) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &heartbeat_panic_nb); register_reboot_notifier(&heartbeat_reboot_nb); } @@ -200,7 +200,7 @@ static int __init heartbeat_trig_init(void) static void __exit heartbeat_trig_exit(void) { unregister_reboot_notifier(&heartbeat_reboot_nb); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &heartbeat_panic_nb); led_trigger_unregister(&heartbeat_led_trigger); } diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c index a16b99bdaa13..d9d5199cdb2b 100644 --- a/drivers/misc/bcm-vk/bcm_vk_dev.c +++ b/drivers/misc/bcm-vk/bcm_vk_dev.c @@ -1446,7 +1446,7 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent) /* register for panic notifier */ vk->panic_nb.notifier_call = bcm_vk_on_panic; - err = atomic_notifier_chain_register(&panic_notifier_list, + err = atomic_notifier_chain_register(&panic_hypervisor_list, &vk->panic_nb); if (err) { dev_err(dev, "Fail to register panic notifier\n"); @@ -1486,7 +1486,7 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent) bcm_vk_tty_exit(vk); err_unregister_panic_notifier: - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &vk->panic_nb); err_destroy_workqueue: @@ -1559,7 +1559,7 @@ static void bcm_vk_remove(struct pci_dev *pdev) usleep_range(BCM_VK_UCODE_BOOT_US, BCM_VK_UCODE_BOOT_MAX_US); /* unregister panic notifier */ - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &vk->panic_nb); bcm_vk_msg_remove(vk); diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c index 049a12006348..233a71d89477 100644 --- a/drivers/misc/pvpanic/pvpanic.c +++ b/drivers/misc/pvpanic/pvpanic.c @@ -101,7 +101,7 @@ static int pvpanic_init(void) INIT_LIST_HEAD(&pvpanic_list); spin_lock_init(&pvpanic_lock); - atomic_notifier_chain_register(&panic_notifier_list, &pvpanic_panic_nb); + atomic_notifier_chain_register(&panic_hypervisor_list, &pvpanic_panic_nb); return 0; } @@ -109,7 +109,7 @@ module_init(pvpanic_init); static void pvpanic_exit(void) { - atomic_notifier_chain_unregister(&panic_notifier_list, &pvpanic_panic_nb); + atomic_notifier_chain_unregister(&panic_hypervisor_list, &pvpanic_panic_nb); } module_exit(pvpanic_exit); diff --git a/drivers/power/reset/ltc2952-poweroff.c b/drivers/power/reset/ltc2952-poweroff.c index 65d9528cc989..fb5078ba3a69 100644 --- a/drivers/power/reset/ltc2952-poweroff.c +++ b/drivers/power/reset/ltc2952-poweroff.c @@ -279,7 +279,7 @@ static int ltc2952_poweroff_probe(struct platform_device *pdev) pm_power_off = ltc2952_poweroff_kill; data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic; - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &data->panic_notifier); dev_info(&pdev->dev, "probe successful\n"); @@ -293,7 +293,7 @@ static int ltc2952_poweroff_remove(struct platform_device *pdev) pm_power_off = NULL; hrtimer_cancel(&data->timer_trigger); hrtimer_cancel(&data->timer_wde); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_hypervisor_list, &data->panic_notifier); return 0; } diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c index 516783ba950f..768a8a3a9046 100644 --- a/drivers/s390/char/zcore.c +++ b/drivers/s390/char/zcore.c @@ -246,7 +246,7 @@ static int zcore_reboot_and_on_panic_handler(struct notifier_block *self, if (hsa_available) release_hsa(); - return NOTIFY_OK; + return NOTIFY_DONE; } static struct notifier_block zcore_reboot_notifier = { @@ -322,7 +322,8 @@ static int __init zcore_init(void) NULL, &zcore_hsa_fops); register_reboot_notifier(&zcore_reboot_notifier); - atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier); + atomic_notifier_chain_register(&panic_hypervisor_list, + &zcore_on_panic_notifier); return 0; fail: diff --git a/drivers/soc/bcm/brcmstb/pm/pm-arm.c b/drivers/soc/bcm/brcmstb/pm/pm-arm.c index 870686ae042b..babca66c7862 100644 --- a/drivers/soc/bcm/brcmstb/pm/pm-arm.c +++ b/drivers/soc/bcm/brcmstb/pm/pm-arm.c @@ -814,7 +814,7 @@ static int brcmstb_pm_probe(struct platform_device *pdev) goto out; } - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_hypervisor_list, &brcmstb_pm_panic_nb); pm_power_off = brcmstb_pm_poweroff; diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 07dced83a783..0bb9dc0dea04 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -6,6 +6,7 @@ #include extern struct atomic_notifier_head panic_notifier_list; +extern struct atomic_notifier_head panic_hypervisor_list; extern bool crash_kexec_post_notifiers; diff --git a/kernel/panic.c b/kernel/panic.c index 523bc9ccd0e9..ef76f3f9c44d 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -73,6 +73,9 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list); EXPORT_SYMBOL(panic_notifier_list); +ATOMIC_NOTIFIER_HEAD(panic_hypervisor_list); +EXPORT_SYMBOL(panic_hypervisor_list); + static long no_blink(int state) { return 0; @@ -287,6 +290,7 @@ void panic(const char *fmt, ...) * Run any panic handlers, including those that might need to * add information to the kmsg dump output. */ + atomic_notifier_call_chain(&panic_hypervisor_list, PANIC_NOTIFIER, buf); atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf); panic_print_sys_info(false); From patchwork Wed Apr 27 22:49:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829690 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F03E7C43217 for ; Wed, 27 Apr 2022 22:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239183AbiD0W74 (ORCPT ); Wed, 27 Apr 2022 18:59:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240483AbiD0W71 (ORCPT ); Wed, 27 Apr 2022 18:59:27 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C16179157E; Wed, 27 Apr 2022 15:55:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=bXh7kiTIu/oy8MX/xHxFfh1fd2A2HdpodNy0n7WfBok=; b=jgBsYcG7VatVMQNKfpmMmj+KDF XkWdsJfK09vZ2R11ym0rJsLvtM7L6jFVra/wKw7Ru20Q3tXdmM07YvLIKve3XUICHAOg3XVnWAPnC QEU9pWc8Syz13kCBbzgQspePXfSisAbL6GFs+m41GGaRoAAhFREDnjG2ZxSQpo/Uwz68hg3pu2x/D E6IkumXzatKpQWO5lYMxPl1yMWzmsX3DQC96acG0StwdG2kMOMr4xmOgeGsgOcdwakQdld1rcVf3a toHhgvuQnGWFi2MNPNWRfSUHfV6qkAGZNsEtUXlHsz/Hx27noavbMwYx8Z2d6rixzJUQIGNVx4tvy GymC5HQQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqYq-0002L8-2E; Thu, 28 Apr 2022 00:55:04 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Benjamin Herrenschmidt , Catalin Marinas , Florian Fainelli , Frederic Weisbecker , "H. Peter Anvin" , Hari Bathini , Joel Fernandes , Jonathan Hunter , Josh Triplett , Lai Jiangshan , Leo Yan , Mathieu Desnoyers , Mathieu Poirier , Michael Ellerman , Mike Leach , Mikko Perttunen , Neeraj Upadhyay , Nicholas Piggin , Paul Mackerras , Suzuki K Poulose , Thierry Reding , Thomas Bogendoerfer Subject: [PATCH 20/30] panic: Add the panic informational notifier list Date: Wed, 27 Apr 2022 19:49:14 -0300 Message-Id: <20220427224924.592546-21-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The goal of this new panic notifier is to allow its users to register callbacks to run earlier in the panic path than they currently do. This aims at informational mechanisms, like dumping kernel offsets and showing device error data (in case it's simple registers reading, for example) as well as mechanisms to disable log flooding (like hung_task detector / RCU warnings) and the tracing dump_on_oops (when enabled). Any (non-invasive) information that should be provided before kmsg_dump() as well as log flooding preventing code should fit here, as long it offers relatively low risk for kdump. For now, the patch is almost a no-op, although it changes a bit the ordering in which some panic notifiers are executed - specially affected by this are the notifiers responsible for disabling the hung_task detector / RCU warnings, which now run first. In a subsequent patch, the panic path will be refactored, then the panic informational notifiers will effectively run earlier, before ksmg_dump() (and usually before kdump as well). We also defer documenting it all properly in the subsequent refactor patch. Finally, while at it, we removed some useless header inclusions too. Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Florian Fainelli Cc: Frederic Weisbecker Cc: "H. Peter Anvin" Cc: Hari Bathini Cc: Joel Fernandes Cc: Jonathan Hunter Cc: Josh Triplett Cc: Lai Jiangshan Cc: Leo Yan Cc: Mathieu Desnoyers Cc: Mathieu Poirier Cc: Michael Ellerman Cc: Mike Leach Cc: Mikko Perttunen Cc: Neeraj Upadhyay Cc: Nicholas Piggin Cc: Paul Mackerras Cc: Suzuki K Poulose Cc: Thierry Reding Cc: Thomas Bogendoerfer Signed-off-by: Guilherme G. Piccoli Acked-by: Paul E. McKenney Acked-by: Suzuki K Poulose --- arch/arm64/kernel/setup.c | 2 +- arch/mips/kernel/relocate.c | 2 +- arch/powerpc/kernel/setup-common.c | 2 +- arch/x86/kernel/setup.c | 2 +- drivers/bus/brcmstb_gisb.c | 2 +- drivers/hwtracing/coresight/coresight-cpu-debug.c | 4 ++-- drivers/soc/tegra/ari-tegra186.c | 3 ++- include/linux/panic_notifier.h | 1 + kernel/hung_task.c | 3 ++- kernel/panic.c | 4 ++++ kernel/rcu/tree.c | 1 - kernel/rcu/tree_stall.h | 3 ++- kernel/trace/trace.c | 2 +- 13 files changed, 19 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 3505789cf4bd..ac2c7e8c9c6a 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -444,7 +444,7 @@ static struct notifier_block arm64_panic_block = { static int __init register_arm64_panic_block(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &arm64_panic_block); return 0; } diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c index 56b51de2dc51..650811f2436a 100644 --- a/arch/mips/kernel/relocate.c +++ b/arch/mips/kernel/relocate.c @@ -459,7 +459,7 @@ static struct notifier_block kernel_location_notifier = { static int __init register_kernel_offset_dumper(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &kernel_location_notifier); return 0; } diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 1468c3937bf4..d04b8bf8dbc7 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -757,7 +757,7 @@ void __init setup_panic(void) &ppc_fadump_block); if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &kernel_offset_notifier); /* Low-level platform-specific routines that should run on panic */ diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index c95b9ac5a457..599b25346964 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1266,7 +1266,7 @@ static struct notifier_block kernel_offset_notifier = { static int __init register_kernel_offset_dumper(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &kernel_offset_notifier); return 0; } diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c index 1ea7b015e225..c64e087fba7a 100644 --- a/drivers/bus/brcmstb_gisb.c +++ b/drivers/bus/brcmstb_gisb.c @@ -486,7 +486,7 @@ static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev) if (list_is_singular(&brcmstb_gisb_arb_device_list)) { register_die_notifier(&gisb_die_notifier); - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &gisb_panic_notifier); } diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c index 1874df7c6a73..7b1012454525 100644 --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c @@ -535,7 +535,7 @@ static int debug_func_init(void) &debug_func_knob_fops); /* Register function to be called for panic */ - ret = atomic_notifier_chain_register(&panic_notifier_list, + ret = atomic_notifier_chain_register(&panic_info_list, &debug_notifier); if (ret) { pr_err("%s: unable to register notifier: %d\n", @@ -552,7 +552,7 @@ static int debug_func_init(void) static void debug_func_exit(void) { - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_info_list, &debug_notifier); debugfs_remove_recursive(debug_debugfs_dir); } diff --git a/drivers/soc/tegra/ari-tegra186.c b/drivers/soc/tegra/ari-tegra186.c index 02577853ec49..4ef05ebed739 100644 --- a/drivers/soc/tegra/ari-tegra186.c +++ b/drivers/soc/tegra/ari-tegra186.c @@ -73,7 +73,8 @@ static struct notifier_block tegra186_ari_panic_nb = { static int __init tegra186_ari_init(void) { if (of_machine_is_compatible("nvidia,tegra186")) - atomic_notifier_chain_register(&panic_notifier_list, &tegra186_ari_panic_nb); + atomic_notifier_chain_register(&panic_info_list, + &tegra186_ari_panic_nb); return 0; } diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 0bb9dc0dea04..7364a346bcb0 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -7,6 +7,7 @@ extern struct atomic_notifier_head panic_notifier_list; extern struct atomic_notifier_head panic_hypervisor_list; +extern struct atomic_notifier_head panic_info_list; extern bool crash_kexec_post_notifiers; diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 52501e5f7655..1b2d7111d5ac 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -85,6 +85,7 @@ hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr) static struct notifier_block panic_block = { .notifier_call = hung_task_panic, + .priority = INT_MAX, /* run early to prevent potential log flood */ }; static void check_hung_task(struct task_struct *t, unsigned long timeout) @@ -378,7 +379,7 @@ static int watchdog(void *dummy) static int __init hung_task_init(void) { - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); + atomic_notifier_chain_register(&panic_info_list, &panic_block); /* Disable hung task detector on suspend */ pm_notifier(hungtask_pm_notify, 0); diff --git a/kernel/panic.c b/kernel/panic.c index ef76f3f9c44d..73ca1bc44e30 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -76,6 +76,9 @@ EXPORT_SYMBOL(panic_notifier_list); ATOMIC_NOTIFIER_HEAD(panic_hypervisor_list); EXPORT_SYMBOL(panic_hypervisor_list); +ATOMIC_NOTIFIER_HEAD(panic_info_list); +EXPORT_SYMBOL(panic_info_list); + static long no_blink(int state) { return 0; @@ -291,6 +294,7 @@ void panic(const char *fmt, ...) * add information to the kmsg dump output. */ atomic_notifier_call_chain(&panic_hypervisor_list, PANIC_NOTIFIER, buf); + atomic_notifier_call_chain(&panic_info_list, PANIC_NOTIFIER, buf); atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf); panic_print_sys_info(false); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a4b8189455d5..d5a2674ae81c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -35,7 +35,6 @@ #include #include #include -#include #include #include #include diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 0c5d8516516a..d8a5840aad5d 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -97,11 +97,12 @@ static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) static struct notifier_block rcu_panic_block = { .notifier_call = rcu_panic, + .priority = INT_MAX, /* run early to prevent potential log flood */ }; static int __init check_cpu_stall_init(void) { - atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block); + atomic_notifier_chain_register(&panic_info_list, &rcu_panic_block); return 0; } early_initcall(check_cpu_stall_init); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c1d8a3622ccc..7d02f7a66bb1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -10138,7 +10138,7 @@ __init static int tracer_alloc_buffers(void) /* All seems OK, enable tracing */ tracing_disabled = 0; - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_info_list, &trace_panic_notifier); register_die_notifier(&trace_die_notifier); From patchwork Wed Apr 27 22:49:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829694 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACC95C4332F for ; Wed, 27 Apr 2022 22:58:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239916AbiD0XBn (ORCPT ); Wed, 27 Apr 2022 19:01:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240832AbiD0W7j (ORCPT ); Wed, 27 Apr 2022 18:59:39 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14413B3DF1; Wed, 27 Apr 2022 15:55:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=UUXOjzoPDzZBxDSM8+K/LI8aYgpN2c+7zHoVbuhOqsQ=; b=GGfx5lsx2iN56x4Z6fieodmwsm q5qfqcY1rIx/L0anA1ZhdBtfQ+C+QCp0EQXWthQC9bhiRHlIzjMM6Fai8Z+t+xthEq/n/fGHRhca/ t9Tdct8qfeyGi9778oHb6Zp3iyEA8AXWsWrvXe98bM5ZSZw4rYAVPyzYJKBGFZSDrdbdRw4ILVA7u KrQ45Y/jrJev8kEITG8FJSs6FiCCu2Z5s5Ob31DxZ15wgRyUmwlyCjKzYxUnHRGrORvmLbjL/1wFO iOOLnSiYgX9k/pD9XDR6G4JrDmutJFroQFiYtMUVMnYe6vm1fC5e6345ak3oNfUcNqnNarGdGEYIA SoanUEvg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqZ3-0002M7-VZ; Thu, 28 Apr 2022 00:55:19 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Alex Elder , Alexander Gordeev , Anton Ivanov , Benjamin Herrenschmidt , Bjorn Andersson , Boris Ostrovsky , Chris Zankel , Christian Borntraeger , Corey Minyard , Dexuan Cui , "H. Peter Anvin" , Haiyang Zhang , Heiko Carstens , Helge Deller , Ivan Kokshaysky , "James E.J. Bottomley" , James Morse , Johannes Berg , "K. Y. Srinivasan" , Mathieu Poirier , Matt Turner , Mauro Carvalho Chehab , Max Filippov , Michael Ellerman , Paul Mackerras , Pavel Machek , Richard Henderson , Richard Weinberger , Robert Richter , Stefano Stabellini , Stephen Hemminger , Sven Schnelle , Tony Luck , Vasily Gorbik , Wei Liu Subject: [PATCH 21/30] panic: Introduce the panic pre-reboot notifier list Date: Wed, 27 Apr 2022 19:49:15 -0300 Message-Id: <20220427224924.592546-22-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org This patch renames the panic_notifier_list to panic_pre_reboot_list; the idea is that a subsequent patch will refactor the panic path in order to better split the notifiers, running some of them very early, some of them not so early [but still before kmsg_dump()] and finally, the rest should execute late, after kdump. The latter ones are now in the panic pre-reboot list - the name comes from the idea that these notifiers execute before panic() attempts rebooting the machine (if that option is set). We also took the opportunity to clean-up useless header inclusions, improve some notifier block declarations (e.g. in ibmasm/heartbeat.c) and more important, change some priorities - we hereby set 2 notifiers to run late in the list [iss_panic_event() and the IPMI panic_event()] due to the risks they offer (may not return, for example). Proper documentation is going to be provided in a subsequent patch, that effectively refactors the panic path. Cc: Alex Elder Cc: Alexander Gordeev Cc: Anton Ivanov Cc: Benjamin Herrenschmidt Cc: Bjorn Andersson Cc: Boris Ostrovsky Cc: Chris Zankel Cc: Christian Borntraeger Cc: Corey Minyard Cc: Dexuan Cui Cc: "H. Peter Anvin" Cc: Haiyang Zhang Cc: Heiko Carstens Cc: Helge Deller Cc: Ivan Kokshaysky Cc: "James E.J. Bottomley" Cc: James Morse Cc: Johannes Berg Cc: Juergen Gross Cc: "K. Y. Srinivasan" Cc: Mathieu Poirier Cc: Matt Turner Cc: Mauro Carvalho Chehab Cc: Max Filippov Cc: Michael Ellerman Cc: Paul Mackerras Cc: Pavel Machek Cc: Richard Henderson Cc: Richard Weinberger Cc: Robert Richter Cc: Stefano Stabellini Cc: Stephen Hemminger Cc: Sven Schnelle Cc: Tony Luck Cc: Vasily Gorbik Cc: Wei Liu Signed-off-by: Guilherme G. Piccoli Acked-by: Alex Elder Acked-by: Corey Minyard Acked-by: Max Filippov --- Notice that, with this name change, out-of-tree code that relies in the global exported "panic_notifier_list" will fail to build. We could easily keep the retro-compatibility by making the old symbol to still exist and point to the pre_reboot list (or even, keep the old naming). But our design choice was to allow the breakage, making users rethink their notifiers, adding them in the list that fits best. If that wasn't a good decision, we're open to change it, of course. Thanks in advance for the review! arch/alpha/kernel/setup.c | 4 ++-- arch/parisc/kernel/pdc_chassis.c | 3 +-- arch/powerpc/kernel/setup-common.c | 2 +- arch/s390/kernel/ipl.c | 4 ++-- arch/um/drivers/mconsole_kern.c | 2 +- arch/um/kernel/um_arch.c | 2 +- arch/x86/xen/enlighten.c | 2 +- arch/xtensa/platforms/iss/setup.c | 4 ++-- drivers/char/ipmi/ipmi_msghandler.c | 12 +++++++----- drivers/edac/altera_edac.c | 3 +-- drivers/hv/vmbus_drv.c | 4 ++-- drivers/leds/trigger/ledtrig-panic.c | 3 +-- drivers/misc/ibmasm/heartbeat.c | 16 +++++++++------- drivers/net/ipa/ipa_smp2p.c | 5 ++--- drivers/parisc/power.c | 4 ++-- drivers/remoteproc/remoteproc_core.c | 6 ++++-- drivers/s390/char/con3215.c | 2 +- drivers/s390/char/con3270.c | 2 +- drivers/s390/char/sclp_con.c | 2 +- drivers/s390/char/sclp_vt220.c | 2 +- drivers/staging/olpc_dcon/olpc_dcon.c | 6 ++++-- drivers/video/fbdev/hyperv_fb.c | 4 ++-- include/linux/panic_notifier.h | 2 +- kernel/panic.c | 9 ++++----- 24 files changed, 54 insertions(+), 51 deletions(-) diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c index d88bdf852753..8ace0d7113b6 100644 --- a/arch/alpha/kernel/setup.c +++ b/arch/alpha/kernel/setup.c @@ -472,8 +472,8 @@ setup_arch(char **cmdline_p) } /* Register a call for panic conditions. */ - atomic_notifier_chain_register(&panic_notifier_list, - &alpha_panic_block); + atomic_notifier_chain_register(&panic_pre_reboot_list, + &alpha_panic_block); #ifndef alpha_using_srm /* Assume that we've booted from SRM if we haven't booted from MILO. diff --git a/arch/parisc/kernel/pdc_chassis.c b/arch/parisc/kernel/pdc_chassis.c index da154406d368..0fd8d87fb4f9 100644 --- a/arch/parisc/kernel/pdc_chassis.c +++ b/arch/parisc/kernel/pdc_chassis.c @@ -22,7 +22,6 @@ #include #include #include -#include #include #include #include @@ -135,7 +134,7 @@ void __init parisc_pdc_chassis_init(void) PDC_CHASSIS_VER); /* initialize panic notifier chain */ - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &pdc_chassis_panic_block); /* initialize reboot notifier chain */ diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index d04b8bf8dbc7..3518bebc10ad 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -762,7 +762,7 @@ void __init setup_panic(void) /* Low-level platform-specific routines that should run on panic */ if (ppc_md.panic) - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &ppc_panic_block); } diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c index 1cc85b8ff42e..4a88c5bb6e15 100644 --- a/arch/s390/kernel/ipl.c +++ b/arch/s390/kernel/ipl.c @@ -2034,7 +2034,7 @@ static int on_panic_notify(struct notifier_block *self, unsigned long event, void *data) { do_panic(); - return NOTIFY_OK; + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { @@ -2069,7 +2069,7 @@ void __init setup_ipl(void) /* We have no info to copy */ break; } - atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb); } void s390_reset_system(void) diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 2ea0421bcc3f..21c13b4e24a3 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -855,7 +855,7 @@ static struct notifier_block panic_exit_notifier = { static int add_notifier(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &panic_exit_notifier); return 0; } diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 4485b1a7c8e4..fc6e443299da 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -257,7 +257,7 @@ static struct notifier_block panic_exit_notifier = { void uml_finishsetup(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &panic_exit_notifier); uml_postsetup(); diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 30c6e986a6cd..d4f4de239a21 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -290,7 +290,7 @@ static struct notifier_block xen_panic_block = { int xen_panic_handler_init(void) { - atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); + atomic_notifier_chain_register(&panic_pre_reboot_list, &xen_panic_block); return 0; } diff --git a/arch/xtensa/platforms/iss/setup.c b/arch/xtensa/platforms/iss/setup.c index d3433e1bb94e..eeeeb6cff6bd 100644 --- a/arch/xtensa/platforms/iss/setup.c +++ b/arch/xtensa/platforms/iss/setup.c @@ -13,7 +13,6 @@ */ #include #include -#include #include #include #include @@ -53,6 +52,7 @@ iss_panic_event(struct notifier_block *this, unsigned long event, void *ptr) static struct notifier_block iss_panic_block = { .notifier_call = iss_panic_event, + .priority = INT_MIN, /* run as late as possible, may not return */ }; void __init platform_setup(char **p_cmdline) @@ -81,5 +81,5 @@ void __init platform_setup(char **p_cmdline) } } - atomic_notifier_chain_register(&panic_notifier_list, &iss_panic_block); + atomic_notifier_chain_register(&panic_pre_reboot_list, &iss_panic_block); } diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index c59265146e9c..6c4770949c01 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -25,7 +25,6 @@ #include #include #include -#include #include #include #include @@ -5375,10 +5374,13 @@ static int ipmi_register_driver(void) return rv; } +/* + * we should execute this panic callback late, since it involves + * a complex call-chain and panic() runs in atomic context. + */ static struct notifier_block panic_block = { .notifier_call = panic_event, - .next = NULL, - .priority = 200 /* priority: INT_MAX >= x >= 0 */ + .priority = INT_MIN + 1, }; static int ipmi_init_msghandler(void) @@ -5406,7 +5408,7 @@ static int ipmi_init_msghandler(void) timer_setup(&ipmi_timer, ipmi_timeout, 0); mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES); - atomic_notifier_chain_register(&panic_notifier_list, &panic_block); + atomic_notifier_chain_register(&panic_pre_reboot_list, &panic_block); initialized = true; @@ -5438,7 +5440,7 @@ static void __exit cleanup_ipmi(void) if (initialized) { destroy_workqueue(remove_work_wq); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_pre_reboot_list, &panic_block); /* diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c index e7e8e624a436..4890e9cba6fb 100644 --- a/drivers/edac/altera_edac.c +++ b/drivers/edac/altera_edac.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include #include @@ -2163,7 +2162,7 @@ static int altr_edac_a10_probe(struct platform_device *pdev) int dberror, err_addr; edac->panic_notifier.notifier_call = s10_edac_dberr_handler; - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &edac->panic_notifier); /* Printout a message if uncorrectable error previously. */ diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 901b97034308..3717c323aa36 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1622,7 +1622,7 @@ static int vmbus_bus_init(void) * Always register the vmbus unload panic notifier because we * need to shut the VMbus channel connection on panic. */ - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &hyperv_panic_vmbus_unload_block); vmbus_request_offers(); @@ -2851,7 +2851,7 @@ static void __exit vmbus_exit(void) * The vmbus panic notifier is always registered, hence we should * also unconditionally unregister it here as well. */ - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_pre_reboot_list, &hyperv_panic_vmbus_unload_block); free_page((unsigned long)hv_panic_page); diff --git a/drivers/leds/trigger/ledtrig-panic.c b/drivers/leds/trigger/ledtrig-panic.c index 64abf2e91608..34fd5170723f 100644 --- a/drivers/leds/trigger/ledtrig-panic.c +++ b/drivers/leds/trigger/ledtrig-panic.c @@ -7,7 +7,6 @@ #include #include -#include #include #include #include "../leds.h" @@ -64,7 +63,7 @@ static long led_panic_blink(int state) static int __init ledtrig_panic_init(void) { - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &led_trigger_panic_nb); led_trigger_register_simple("panic", &trigger); diff --git a/drivers/misc/ibmasm/heartbeat.c b/drivers/misc/ibmasm/heartbeat.c index 59c9a0d95659..d6acae88b722 100644 --- a/drivers/misc/ibmasm/heartbeat.c +++ b/drivers/misc/ibmasm/heartbeat.c @@ -8,7 +8,6 @@ * Author: Max Asböck */ -#include #include #include "ibmasm.h" #include "dot_command.h" @@ -24,7 +23,7 @@ static int suspend_heartbeats = 0; * In the case of a panic the interrupt handler continues to work and thus * continues to respond to heartbeats, making the service processor believe * the OS is still running and thus preventing a reboot. - * To prevent this from happening a callback is added the panic_notifier_list. + * To prevent this from happening a callback is added in a panic notifier list. * Before responding to a heartbeat the driver checks if a panic has happened, * if yes it suspends heartbeat, causing the service processor to reboot as * expected. @@ -32,20 +31,23 @@ static int suspend_heartbeats = 0; static int panic_happened(struct notifier_block *n, unsigned long val, void *v) { suspend_heartbeats = 1; - return 0; + return NOTIFY_DONE; } -static struct notifier_block panic_notifier = { panic_happened, NULL, 1 }; +static struct notifier_block panic_notifier = { + .notifier_call = panic_happened, +}; void ibmasm_register_panic_notifier(void) { - atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier); + atomic_notifier_chain_register(&panic_pre_reboot_list, + &panic_notifier); } void ibmasm_unregister_panic_notifier(void) { - atomic_notifier_chain_unregister(&panic_notifier_list, - &panic_notifier); + atomic_notifier_chain_unregister(&panic_pre_reboot_list, + &panic_notifier); } diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c index 211233612039..92cdf6e0637c 100644 --- a/drivers/net/ipa/ipa_smp2p.c +++ b/drivers/net/ipa/ipa_smp2p.c @@ -7,7 +7,6 @@ #include #include #include -#include #include #include #include @@ -138,13 +137,13 @@ static int ipa_smp2p_panic_notifier_register(struct ipa_smp2p *smp2p) smp2p->panic_notifier.notifier_call = ipa_smp2p_panic_notifier; smp2p->panic_notifier.priority = INT_MAX; /* Do it early */ - return atomic_notifier_chain_register(&panic_notifier_list, + return atomic_notifier_chain_register(&panic_pre_reboot_list, &smp2p->panic_notifier); } static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p) { - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_pre_reboot_list, &smp2p->panic_notifier); } diff --git a/drivers/parisc/power.c b/drivers/parisc/power.c index 8512884de2cf..5bb0868f5f08 100644 --- a/drivers/parisc/power.c +++ b/drivers/parisc/power.c @@ -233,7 +233,7 @@ static int __init power_init(void) } /* Register a call for panic conditions. */ - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &parisc_panic_block); return 0; @@ -243,7 +243,7 @@ static void __exit power_exit(void) { kthread_stop(power_task); - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_pre_reboot_list, &parisc_panic_block); pdc_soft_power_button(0); diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c index c510125769b9..24799ff239e6 100644 --- a/drivers/remoteproc/remoteproc_core.c +++ b/drivers/remoteproc/remoteproc_core.c @@ -2795,12 +2795,14 @@ static int rproc_panic_handler(struct notifier_block *nb, unsigned long event, static void __init rproc_init_panic(void) { rproc_panic_nb.notifier_call = rproc_panic_handler; - atomic_notifier_chain_register(&panic_notifier_list, &rproc_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, + &rproc_panic_nb); } static void __exit rproc_exit_panic(void) { - atomic_notifier_chain_unregister(&panic_notifier_list, &rproc_panic_nb); + atomic_notifier_chain_unregister(&panic_pre_reboot_list, + &rproc_panic_nb); } static int __init remoteproc_init(void) diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c index 192198bd3dc4..07379dd3f1f3 100644 --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -867,7 +867,7 @@ static int __init con3215_init(void) raw3215[0] = NULL; return -ENODEV; } - atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb); register_reboot_notifier(&on_reboot_nb); register_console(&con3215); return 0; diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c index 476202f3d8a0..e79bf3e7bde3 100644 --- a/drivers/s390/char/con3270.c +++ b/drivers/s390/char/con3270.c @@ -645,7 +645,7 @@ con3270_init(void) condev->cline->len = 0; con3270_create_status(condev); condev->input = alloc_string(&condev->freemem, 80); - atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb); register_reboot_notifier(&on_reboot_nb); register_console(&con3270); return 0; diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index e5d947c763ea..7ca9d4c45d60 100644 --- a/drivers/s390/char/sclp_con.c +++ b/drivers/s390/char/sclp_con.c @@ -288,7 +288,7 @@ sclp_console_init(void) timer_setup(&sclp_con_timer, sclp_console_timeout, 0); /* enable printk-access to this driver */ - atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb); register_reboot_notifier(&on_reboot_nb); register_console(&sclp_console); return 0; diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index a32f34a1c6d2..97cf9e290c28 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -838,7 +838,7 @@ sclp_vt220_con_init(void) if (rc) return rc; /* Attach linux console */ - atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, &on_panic_nb); register_reboot_notifier(&on_reboot_nb); register_console(&sclp_vt220_console); return 0; diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c b/drivers/staging/olpc_dcon/olpc_dcon.c index 7284cb4ac395..cb50471f2246 100644 --- a/drivers/staging/olpc_dcon/olpc_dcon.c +++ b/drivers/staging/olpc_dcon/olpc_dcon.c @@ -653,7 +653,8 @@ static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id) } register_reboot_notifier(&dcon->reboot_nb); - atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb); + atomic_notifier_chain_register(&panic_pre_reboot_list, + &dcon_panic_nb); return 0; @@ -676,7 +677,8 @@ static int dcon_remove(struct i2c_client *client) struct dcon_priv *dcon = i2c_get_clientdata(client); unregister_reboot_notifier(&dcon->reboot_nb); - atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb); + atomic_notifier_chain_unregister(&panic_pre_reboot_list, + &dcon_panic_nb); free_irq(DCON_IRQ, dcon); diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c index f3494b868a64..ec21e63592be 100644 --- a/drivers/video/fbdev/hyperv_fb.c +++ b/drivers/video/fbdev/hyperv_fb.c @@ -1253,7 +1253,7 @@ static int hvfb_probe(struct hv_device *hdev, */ par->hvfb_panic_nb.notifier_call = hvfb_on_panic; par->hvfb_panic_nb.priority = INT_MIN + 10, - atomic_notifier_chain_register(&panic_notifier_list, + atomic_notifier_chain_register(&panic_pre_reboot_list, &par->hvfb_panic_nb); return 0; @@ -1276,7 +1276,7 @@ static int hvfb_remove(struct hv_device *hdev) struct fb_info *info = hv_get_drvdata(hdev); struct hvfb_par *par = info->par; - atomic_notifier_chain_unregister(&panic_notifier_list, + atomic_notifier_chain_unregister(&panic_pre_reboot_list, &par->hvfb_panic_nb); par->update = false; diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 7364a346bcb0..7912aacbc0e5 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -5,9 +5,9 @@ #include #include -extern struct atomic_notifier_head panic_notifier_list; extern struct atomic_notifier_head panic_hypervisor_list; extern struct atomic_notifier_head panic_info_list; +extern struct atomic_notifier_head panic_pre_reboot_list; extern bool crash_kexec_post_notifiers; diff --git a/kernel/panic.c b/kernel/panic.c index 73ca1bc44e30..a9d43b98b05b 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -69,16 +69,15 @@ EXPORT_SYMBOL_GPL(panic_timeout); #define PANIC_PRINT_ALL_CPU_BT 0x00000040 unsigned long panic_print; -ATOMIC_NOTIFIER_HEAD(panic_notifier_list); - -EXPORT_SYMBOL(panic_notifier_list); - ATOMIC_NOTIFIER_HEAD(panic_hypervisor_list); EXPORT_SYMBOL(panic_hypervisor_list); ATOMIC_NOTIFIER_HEAD(panic_info_list); EXPORT_SYMBOL(panic_info_list); +ATOMIC_NOTIFIER_HEAD(panic_pre_reboot_list); +EXPORT_SYMBOL(panic_pre_reboot_list); + static long no_blink(int state) { return 0; @@ -295,7 +294,7 @@ void panic(const char *fmt, ...) */ atomic_notifier_call_chain(&panic_hypervisor_list, PANIC_NOTIFIER, buf); atomic_notifier_call_chain(&panic_info_list, PANIC_NOTIFIER, buf); - atomic_notifier_call_chain(&panic_notifier_list, PANIC_NOTIFIER, buf); + atomic_notifier_call_chain(&panic_pre_reboot_list, PANIC_NOTIFIER, buf); panic_print_sys_info(false); From patchwork Wed Apr 27 22:49:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829753 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB4A9C4332F for ; Wed, 27 Apr 2022 23:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240048AbiD0XDd (ORCPT ); Wed, 27 Apr 2022 19:03:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239847AbiD0XBi (ORCPT ); Wed, 27 Apr 2022 19:01:38 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 849A61BEBE; Wed, 27 Apr 2022 15:55:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=VYrOPrqDKiFUsTfjme0J+bb1QZ+0oMPMNlfIlQcQCIU=; b=esIQjYNUmn8XOAMCY8KOPnZ+c+ YZlzZFZJpud7l5aihfe1Itrd6ZZ98nnyy8UW1vOI1POK9zaRsPqoo2RhL4mEx84eRCHYefMesX5mG VJrQ0svjjO9G7VgOzDpcDLV/ntiz5AJExQTPCtbTdt7JFiAMS9guj375T3WC2+gnc5gFYq3Gv7f9R ZGEBpB02C9AAgh+86UxcqyV3yEw/FrOPinej5D7IeCAr0QV77wv10T31rCvUIuA1DrjRAh9qz2P38 INNgxs5Kiy35sxcHJ/zXmQv2S2dVW6xiWlXVQ/tXuVpNtfQbdJCWgDKWsqK11QKSPuRppT31lgGJ9 pH1ZqjsQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqZZ-0002Nv-Ix; Thu, 28 Apr 2022 00:55:50 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Alexander Gordeev , Christian Borntraeger , "David S. Miller" , Heiko Carstens , Sven Schnelle , Vasily Gorbik Subject: [PATCH 22/30] panic: Introduce the panic post-reboot notifier list Date: Wed, 27 Apr 2022 19:49:16 -0300 Message-Id: <20220427224924.592546-23-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently we have 3 notifier lists in the panic path, which will be wired in a way to allow the notifier callbacks to run in different moments at panic time, in a subsequent patch. But there is also an odd set of architecture calls hardcoded in the end of panic path, after the restart machinery. They're responsible for late time tunings / events, like enabling a stop button (Sparc) or effectively stopping the machine (s390). This patch introduces yet another notifier list to offer the architectures a way to add callbacks in such late moment on panic path without the need of ifdefs / hardcoded approaches. Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: "David S. Miller" Cc: Heiko Carstens Cc: Sven Schnelle Cc: Vasily Gorbik Signed-off-by: Guilherme G. Piccoli Acked-by: Heiko Carstens --- arch/s390/kernel/setup.c | 19 ++++++++++++++++++- arch/sparc/kernel/setup_32.c | 27 +++++++++++++++++++++++---- arch/sparc/kernel/setup_64.c | 29 ++++++++++++++++++++++++----- include/linux/panic_notifier.h | 1 + kernel/panic.c | 19 +++++++------------ 5 files changed, 73 insertions(+), 22 deletions(-) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index d860ac300919..d816b2045f1e 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -39,7 +39,6 @@ #include #include #include -#include #include #include #include @@ -51,6 +50,7 @@ #include #include #include +#include #include #include @@ -943,6 +943,20 @@ static void __init log_component_list(void) } } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + disabled_wait(); + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + /* * Setup function called from init/main.c just after the banner * was printed. @@ -1058,4 +1072,7 @@ void __init setup_arch(char **cmdline_p) /* Add system specific data to the random pool */ setup_randomness(); + + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); } diff --git a/arch/sparc/kernel/setup_32.c b/arch/sparc/kernel/setup_32.c index c8e0dd99f370..4e2428972f76 100644 --- a/arch/sparc/kernel/setup_32.c +++ b/arch/sparc/kernel/setup_32.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include @@ -51,6 +52,7 @@ #include "kernel.h" +int stop_a_enabled = 1; struct screen_info screen_info = { 0, 0, /* orig-x, orig-y */ 0, /* unused */ @@ -293,6 +295,24 @@ void __init sparc32_start_kernel(struct linux_romvec *rp) start_kernel(); } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + /* Make sure the user can actually press Stop-A (L1-A) */ + stop_a_enabled = 1; + pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" + "twice on console to return to the boot prom\n"); + + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + void __init setup_arch(char **cmdline_p) { int i; @@ -368,9 +388,10 @@ void __init setup_arch(char **cmdline_p) paging_init(); smp_setup_cpu_possible_map(); -} -extern int stop_a_enabled; + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); +} void sun_do_break(void) { @@ -384,8 +405,6 @@ void sun_do_break(void) } EXPORT_SYMBOL(sun_do_break); -int stop_a_enabled = 1; - static int __init topology_init(void) { int i, ncpus, err; diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c index 48abee4eee29..9066c25ecc07 100644 --- a/arch/sparc/kernel/setup_64.c +++ b/arch/sparc/kernel/setup_64.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -62,6 +63,8 @@ #include "entry.h" #include "kernel.h" +int stop_a_enabled = 1; + /* Used to synchronize accesses to NatSemi SUPER I/O chip configure * operations in asm/ns87303.h */ @@ -632,6 +635,24 @@ void __init alloc_irqstack_bootmem(void) } } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + /* Make sure the user can actually press Stop-A (L1-A) */ + stop_a_enabled = 1; + pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" + "twice on console to return to the boot prom\n"); + + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + void __init setup_arch(char **cmdline_p) { /* Initialize PROM console and command line. */ @@ -691,9 +712,10 @@ void __init setup_arch(char **cmdline_p) * allocate the IRQ stacks. */ alloc_irqstack_bootmem(); -} -extern int stop_a_enabled; + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); +} void sun_do_break(void) { @@ -706,6 +728,3 @@ void sun_do_break(void) prom_cmdline(); } EXPORT_SYMBOL(sun_do_break); - -int stop_a_enabled = 1; -EXPORT_SYMBOL(stop_a_enabled); diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 7912aacbc0e5..bcf6a5ea9d7f 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -8,6 +8,7 @@ extern struct atomic_notifier_head panic_hypervisor_list; extern struct atomic_notifier_head panic_info_list; extern struct atomic_notifier_head panic_pre_reboot_list; +extern struct atomic_notifier_head panic_post_reboot_list; extern bool crash_kexec_post_notifiers; diff --git a/kernel/panic.c b/kernel/panic.c index a9d43b98b05b..bf792102b43e 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -78,6 +78,9 @@ EXPORT_SYMBOL(panic_info_list); ATOMIC_NOTIFIER_HEAD(panic_pre_reboot_list); EXPORT_SYMBOL(panic_pre_reboot_list); +ATOMIC_NOTIFIER_HEAD(panic_post_reboot_list); +EXPORT_SYMBOL(panic_post_reboot_list); + static long no_blink(int state) { return 0; @@ -359,18 +362,10 @@ void panic(const char *fmt, ...) reboot_mode = panic_reboot_mode; emergency_restart(); } -#ifdef __sparc__ - { - extern int stop_a_enabled; - /* Make sure the user can actually press Stop-A (L1-A) */ - stop_a_enabled = 1; - pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" - "twice on console to return to the boot prom\n"); - } -#endif -#if defined(CONFIG_S390) - disabled_wait(); -#endif + + atomic_notifier_call_chain(&panic_post_reboot_list, + PANIC_NOTIFIER, buf); + pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); /* Do not scroll important messages printed above */ From patchwork Wed Apr 27 22:49:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829754 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E4CEC433EF for ; Wed, 27 Apr 2022 23:00:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233973AbiD0XDv (ORCPT ); Wed, 27 Apr 2022 19:03:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239843AbiD0XBi (ORCPT ); Wed, 27 Apr 2022 19:01:38 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0698E4EF42; Wed, 27 Apr 2022 15:56:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=durrkKWmzUfzH9qHOG14tQL4R8NCjUjLsTL3Zd00Gek=; b=My7iXYZdsvmohLkJmMGImfYof2 p5qkpSJIhXISH+Sbyoj7EeJcOzhmrD5DtjdC6ethktkBlGYO4OfumrpixOUOKLn0Yc0W3TzG54aQY qwtzEOPADTIziH/itInY9Ffg69Sdqh65llZVZNXQlNolBLE2NFdio5E/kUq6oVXX/i2DBK4KweBxr JYm/gjauE4ZVcDNk28sbO0j6B73HXBblZWGmkswBaL+iIGNqLKObr06z5uxWmvVGTIOTQmQ/deHWL LutJobNbiLmganjaFUa+PvHzE64AyIeADEi0jWz8oHx43nzynoDLyNtzoi4XrtuDHAtIno5r39V8q Qw3pgkkw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqZo-0002Om-0k; Thu, 28 Apr 2022 00:56:04 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 23/30] printk: kmsg_dump: Introduce helper to inform number of dumpers Date: Wed, 27 Apr 2022 19:49:17 -0300 Message-Id: <20220427224924.592546-24-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently we don't have a way to check if there are dumpers set, except counting the list members maybe. This patch introduces a very simple helper to provide this information, by just keeping track of registered/unregistered kmsg dumpers. It's going to be used on the panic path in the subsequent patch. Notice that the spinlock guarding kmsg_dumpers list also guards increment/decrement of the dumper's counter, but there's no need for that when reading the counter in the panic path, since that is an atomic path and there's no other (planned) user. Signed-off-by: Guilherme G. Piccoli Reviewed-by: Petr Mladek --- include/linux/kmsg_dump.h | 7 +++++++ kernel/printk/printk.c | 14 ++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 906521c2329c..abea1974bff8 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -65,6 +65,8 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, void kmsg_dump_rewind(struct kmsg_dump_iter *iter); +bool kmsg_has_dumpers(void); + int kmsg_dump_register(struct kmsg_dumper *dumper); int kmsg_dump_unregister(struct kmsg_dumper *dumper); @@ -91,6 +93,11 @@ static inline void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { } +static inline bool kmsg_has_dumpers(void) +{ + return false; +} + static inline int kmsg_dump_register(struct kmsg_dumper *dumper) { return -EINVAL; diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index da03c15ecc89..e3a1c429fbbc 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3399,6 +3399,18 @@ EXPORT_SYMBOL(printk_timed_ratelimit); static DEFINE_SPINLOCK(dump_list_lock); static LIST_HEAD(dump_list); +static int num_dumpers; + +/** + * kmsg_has_dumpers - inform if there is any kmsg dumper registered. + * + * Returns true if there's at least one registered dumper, or false + * if otherwise. + */ +bool kmsg_has_dumpers(void) +{ + return num_dumpers ? true : false; +} /** * kmsg_dump_register - register a kernel log dumper. @@ -3423,6 +3435,7 @@ int kmsg_dump_register(struct kmsg_dumper *dumper) dumper->registered = 1; list_add_tail_rcu(&dumper->list, &dump_list); err = 0; + num_dumpers++; } spin_unlock_irqrestore(&dump_list_lock, flags); @@ -3447,6 +3460,7 @@ int kmsg_dump_unregister(struct kmsg_dumper *dumper) dumper->registered = 0; list_del_rcu(&dumper->list); err = 0; + num_dumpers--; } spin_unlock_irqrestore(&dump_list_lock, flags); synchronize_rcu(); From patchwork Wed Apr 27 22:49:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829755 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E40DC433EF for ; Wed, 27 Apr 2022 23:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239808AbiD0XDy (ORCPT ); Wed, 27 Apr 2022 19:03:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239884AbiD0XBj (ORCPT ); Wed, 27 Apr 2022 19:01:39 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B207560A91; Wed, 27 Apr 2022 15:56:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=HBUuAr51OMuxJxYe3RD+OwNeXP+xs2hLWBMDzaZAVcU=; b=TdeuJAIDaqG7cwkqI4nHtdLny3 iyCGAksOLbOqYUJhSHm7/jnC9FYcG7MIAOI+24axWzVXXtY5atDwJhF+jKUhXmqfua6SRtlM+APMM /pYrjZPc6jxGuTXcpWZNvCBeGuUVSbIdA+s5Wy3xFKjzxGB2gHwr9ssNf9AZuLz8yIIYL86UZuejU XVMh5xio++Mw71vSoYtvIu7OGOfqGzJUfFYq3P814XI3qfdU5eIZpgCj0gTmmOGhFHuiK0SwPAxTu lSlbzkU4S5i7NKFBbNSmypNtm9Lj4sjOaRZ0Un4K1h/t8X5QpXDk7e0wi3PVQ1JnV2KXISI4VvN0g bri/UK8A==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqa3-0002Pf-2B; Thu, 28 Apr 2022 00:56:20 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 24/30] panic: Refactor the panic path Date: Wed, 27 Apr 2022 19:49:18 -0300 Message-Id: <20220427224924.592546-25-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org The panic() function is somewhat convoluted - a lot of changes were made over the years, adding comments that might be misleading/outdated now, it has a code structure that is a bit complex to follow, with lots of conditionals, for example. The panic notifier list is something else - a single list, with multiple callbacks of different purposes, that run in a non-deterministic order and may affect hardly kdump reliability - see the "crash_kexec_post_notifiers" workaround-ish flag. This patch proposes a major refactor on the panic path based on Petr's idea [0] - basically we split the notifiers list in three, having a set of different call points in the panic path. Below a list of changes proposed in this patch, culminating in the panic notifiers level concept: (a) First of all, we improved comments all over the function and removed useless variables / includes. Also, as part of this clean-up we concentrate the console flushing functions in a helper. (b) As mentioned before, there is a split of the panic notifier list in three, based on the purpose of the callback. The code contains good documentation in form of comments, but a summary of the three lists follows: - the hypervisor list aims low-risk procedures to inform hypervisors or firmware about the panic event, also includes LED-related functions; - the informational list contains callbacks that provide more details, like kernel offset or trace dump (if enabled) and also includes the callbacks aimed at reducing log pollution or warns, like the RCU and hung task disable callbacks; - finally, the pre_reboot list is the old notifier list renamed, containing the more risky callbacks that didn't fit the previous lists. There is also a 4th list (the post_reboot one), but it's not related with the original list - it contains late time architecture callbacks aimed at stopping the machine, for example. The 3 notifiers lists execute in different moments, hypervisor being the first, followed by informational and finally the pre_reboot list. (c) But then, there is the ordering problem of the notifiers against the crash_kernel() call - kdump must be as reliable as possible. For that, a simple binary "switch" as "crash_kexec_post_notifiers" is not enough, hence we introduce here concept of panic notifier levels: there are 5 levels, from 0 (no notifier executes before kdump) until 4 (all notifiers run before kdump); the default level is 2, in which the hypervisor and (iff we have any kmsg dumper) the informational notifiers execute before kdump. The detailed documentation of the levels is present in code comments and in the kernel-parameters.txt file; as an analogy with the previous panic() implementation, the level 0 is exactly the same as the old behavior of notifiers, running all after kdump, and the level 4 is the same as "crash_kexec_post_notifiers=Y" (we kept this parameter as a deprecated one). (d) Finally, an important change made here: we now use only the function "crash_smp_send_stop()" to shut all the secondary CPUs in the panic path. Before, there was a case of using the regular "smp_send_stop()", but the better approach is to simplify the code and try to use the function which was created exclusively for the panic path. Experiments showed that it works fine, and code was very simplified with that. Functional change is expected from this refactor, since now we call some notifiers by default before kdump, but the goal here besides code clean-up is to have a better panic path, more reliable and deterministic, but also very customizable. [0] https://lore.kernel.org/lkml/YfPxvzSzDLjO5ldp@alley/ Suggested-by: Petr Mladek Signed-off-by: Guilherme G. Piccoli --- Special thanks to Petr and Baoquan for the suggestion and feedback in a previous email thread. There's some important design decisions that worth mentioning and discussing: * The default panic notifiers level is 2, based on Petr Mladek's suggestion, which makes a lot of sense. Of course, this is customizable through the parameter, but would be something worthwhile to have a KConfig option to set the default level? It would help distros that want the old behavior (no notifiers before kdump) as default. * The implementation choice was to _avoid_ intricate if conditionals in the panic path, which would _definitely_ be present with the panic notifiers levels idea; so, instead of lots of if conditionals, the set/clear bits approach with functions called in 2 points (but executing only in one of them) is much easier to follow an was used here; the ordering helper function and the comments also help a lot to avoid confusion (hopefully). * Choice was to *always* use crash_smp_send_stop() instead of sometimes making use of the regular smp_send_stop(); for most architectures they are the same, including Xen (on x86). For the ones that override it, all should work fine, in the powerpc case it's even more correct (see the subsequent patch "powerpc: Do not force all panic notifiers to execute before kdump") There seems to be 2 cases that requires some plumbing to work 100% right: - ARM doesn't disable local interrupts / FIQs in the crash version of send_stop(); we patched that early in this series; - x86 could face an issue if we have VMX and do use crash_smp_send_stop() _without_ kdump, but this is fixed in the first patch of the series (and it's a bug present even before this refactor). * Notice we didn't add a sysrq for panic notifiers level - should have it? Alejandro proposed recently to add a sysrq for "crash_kexec_post_notifiers", let me know if you feel the need here Alejandro, since the core parameters are present in /sys, I didn't consider much gain in having a sysrq, but of course I'm open to suggestions! Thanks advance for the review! .../admin-guide/kernel-parameters.txt | 42 ++- include/linux/panic_notifier.h | 1 + kernel/kexec_core.c | 8 +- kernel/panic.c | 292 +++++++++++++----- .../selftests/pstore/pstore_crash_test | 5 +- 5 files changed, 252 insertions(+), 96 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3f1cc5e317ed..8d3524060ce3 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -829,6 +829,13 @@ It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. + crash_kexec_post_notifiers + This was DEPRECATED - users should always prefer the + parameter "panic_notifiers_level" - check its entry + in this documentation for details on how it works. + Setting this parameter is exactly the same as setting + "panic_notifiers_level=4". + cryptomgr.notests [KNL] Disable crypto self-tests @@ -3784,6 +3791,33 @@ timeout < 0: reboot immediately Format: + panic_notifiers_level= + [KNL] Set the panic notifiers execution order. + Format: + We currently have 4 lists of panic notifiers; based + on the functionality and risk (for panic success) the + callbacks are added in a given list. The lists are: + - hypervisor/FW notification list (low risk); + - informational list (low/medium risk); + - pre_reboot list (higher risk); + - post_reboot list (only run late in panic and after + kdump, not configurable for now). + This parameter defines the ordering of the first 3 + lists with regards to kdump; the levels determine + which set of notifiers execute before kdump. The + accepted levels are: + 0: kdump is the first thing to run, NO list is + executed before kdump. + 1: only the hypervisor list is executed before kdump. + 2 (default level): the hypervisor list and (*if* + there's any kmsg_dumper defined) the informational + list are executed before kdump. + 3: both the hypervisor and the informational lists + (always) execute before kdump. + 4: the 3 lists (hypervisor, info and pre_reboot) + execute before kdump - this behavior is analog to the + deprecated parameter "crash_kexec_post_notifiers". + panic_print= Bitmask for printing system info when panic happens. User can chose combination of the following bits: bit 0: print all tasks info @@ -3814,14 +3848,6 @@ panic_on_warn panic() instead of WARN(). Useful to cause kdump on a WARN(). - crash_kexec_post_notifiers - Run kdump after running panic-notifiers and dumping - kmsg. This only for the users who doubt kdump always - succeeds in any situation. - Note that this also increases risks of kdump failure, - because some panic notifiers can make the crashed - kernel more unstable. - parkbd.port= [HW] Parallel port number the keyboard adapter is connected to, default is 0. Format: diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index bcf6a5ea9d7f..b5041132321d 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -10,6 +10,7 @@ extern struct atomic_notifier_head panic_info_list; extern struct atomic_notifier_head panic_pre_reboot_list; extern struct atomic_notifier_head panic_post_reboot_list; +bool panic_notifiers_before_kdump(void); extern bool crash_kexec_post_notifiers; enum panic_notifier_val { diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 68480f731192..f8906db8ca72 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -74,11 +74,11 @@ struct resource crashk_low_res = { int kexec_should_crash(struct task_struct *p) { /* - * If crash_kexec_post_notifiers is enabled, don't run - * crash_kexec() here yet, which must be run after panic - * notifiers in panic(). + * In case any panic notifiers are set to execute before kexec, + * don't run crash_kexec() here yet, which must run after these + * panic notifiers are executed, in the panic() path. */ - if (crash_kexec_post_notifiers) + if (panic_notifiers_before_kdump()) return 0; /* * There are 4 panic() calls in make_task_dead() path, each of which diff --git a/kernel/panic.c b/kernel/panic.c index bf792102b43e..b7c055d4f87f 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -52,14 +51,23 @@ static unsigned long tainted_mask = static int pause_on_oops; static int pause_on_oops_flag; static DEFINE_SPINLOCK(pause_on_oops_lock); -bool crash_kexec_post_notifiers; + int panic_on_warn __read_mostly; +bool panic_on_taint_nousertaint; unsigned long panic_on_taint; -bool panic_on_taint_nousertaint = false; int panic_timeout = CONFIG_PANIC_TIMEOUT; EXPORT_SYMBOL_GPL(panic_timeout); +/* Initialized with all notifiers set to run before kdump */ +static unsigned long panic_notifiers_bits = 15; + +/* Default level is 2, see kernel-parameters.txt */ +unsigned int panic_notifiers_level = 2; + +/* DEPRECATED in favor of panic_notifiers_level */ +bool crash_kexec_post_notifiers; + #define PANIC_PRINT_TASK_INFO 0x00000001 #define PANIC_PRINT_MEM_INFO 0x00000002 #define PANIC_PRINT_TIMER_INFO 0x00000004 @@ -109,10 +117,14 @@ void __weak nmi_panic_self_stop(struct pt_regs *regs) } /* - * Stop other CPUs in panic. Architecture dependent code may override this - * with more suitable version. For example, if the architecture supports - * crash dump, it should save registers of each stopped CPU and disable - * per-CPU features such as virtualization extensions. + * Stop other CPUs in panic context. + * + * Architecture dependent code may override this with more suitable version. + * For example, if the architecture supports crash dump, it should save the + * registers of each stopped CPU and disable per-CPU features such as + * virtualization extensions. When not overridden in arch code (and for + * x86/xen), this is exactly the same as execute smp_send_stop(), but + * guarded against duplicate execution. */ void __weak crash_smp_send_stop(void) { @@ -183,6 +195,112 @@ static void panic_print_sys_info(bool console_flush) ftrace_dump(DUMP_ALL); } +/* + * Helper that accumulates all console flushing routines executed on panic. + */ +static void console_flushing(void) +{ +#ifdef CONFIG_VT + unblank_screen(); +#endif + console_unblank(); + + /* + * In this point, we may have disabled other CPUs, hence stopping the + * CPU holding the lock while still having some valuable data in the + * console buffer. + * + * Try to acquire the lock then release it regardless of the result. + * The release will also print the buffers out. Locks debug should + * be disabled to avoid reporting bad unlock balance when panic() + * is not being called from OOPS. + */ + debug_locks_off(); + console_flush_on_panic(CONSOLE_FLUSH_PENDING); + + panic_print_sys_info(true); +} + +#define PN_HYPERVISOR_BIT 0 +#define PN_INFO_BIT 1 +#define PN_PRE_REBOOT_BIT 2 +#define PN_POST_REBOOT_BIT 3 + +/* + * Determine the order of panic notifiers with regards to kdump. + * + * This function relies in the "panic_notifiers_level" kernel parameter + * to determine how to order the notifiers with regards to kdump. We + * have currently 5 levels. For details, please check the kernel docs for + * "panic_notifiers_level" at Documentation/admin-guide/kernel-parameters.txt. + * + * Default level is 2, which means the panic hypervisor and informational + * (unless we don't have any kmsg_dumper) lists will execute before kdump. + */ +static void order_panic_notifiers_and_kdump(void) +{ + /* + * The parameter "crash_kexec_post_notifiers" is deprecated, but + * valid. Users that set it want really all panic notifiers to + * execute before kdump, so it's effectively the same as setting + * the panic notifiers level to 4. + */ + if (panic_notifiers_level >= 4 || crash_kexec_post_notifiers) + return; + + /* + * Based on the level configured (smaller than 4), we clear the + * proper bits in "panic_notifiers_bits". Notice that this bitfield + * is initialized with all notifiers set. + */ + switch (panic_notifiers_level) { + case 3: + clear_bit(PN_PRE_REBOOT_BIT, &panic_notifiers_bits); + break; + case 2: + clear_bit(PN_PRE_REBOOT_BIT, &panic_notifiers_bits); + + if (!kmsg_has_dumpers()) + clear_bit(PN_INFO_BIT, &panic_notifiers_bits); + break; + case 1: + clear_bit(PN_PRE_REBOOT_BIT, &panic_notifiers_bits); + clear_bit(PN_INFO_BIT, &panic_notifiers_bits); + break; + case 0: + clear_bit(PN_PRE_REBOOT_BIT, &panic_notifiers_bits); + clear_bit(PN_INFO_BIT, &panic_notifiers_bits); + clear_bit(PN_HYPERVISOR_BIT, &panic_notifiers_bits); + break; + } +} + +/* + * Set of helpers to execute the panic notifiers only once. + * Just the informational notifier cares about the return. + */ +static inline bool notifier_run_once(struct atomic_notifier_head head, + char *buf, long bit) +{ + if (test_and_change_bit(bit, &panic_notifiers_bits)) { + atomic_notifier_call_chain(&head, PANIC_NOTIFIER, buf); + return true; + } + return false; +} + +#define panic_notifier_hypervisor_once(buf)\ + notifier_run_once(panic_hypervisor_list, buf, PN_HYPERVISOR_BIT) + +#define panic_notifier_info_once(buf)\ + notifier_run_once(panic_info_list, buf, PN_INFO_BIT) + +#define panic_notifier_pre_reboot_once(buf)\ + notifier_run_once(panic_pre_reboot_list, buf, PN_PRE_REBOOT_BIT) + +#define panic_notifier_post_reboot_once(buf)\ + notifier_run_once(panic_post_reboot_list, buf, PN_POST_REBOOT_BIT) + /** * panic - halt the system * @fmt: The text string to print @@ -198,32 +316,29 @@ void panic(const char *fmt, ...) long i, i_next = 0, len; int state = 0; int old_cpu, this_cpu; - bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; - if (panic_on_warn) { - /* - * This thread may hit another WARN() in the panic path. - * Resetting this prevents additional WARN() from panicking the - * system on this thread. Other threads are blocked by the - * panic_mutex in panic(). - */ - panic_on_warn = 0; - } + /* + * This thread may hit another WARN() in the panic path, so + * resetting this option prevents additional WARN() from + * re-panicking the system here. + */ + panic_on_warn = 0; /* * Disable local interrupts. This will prevent panic_smp_self_stop - * from deadlocking the first cpu that invokes the panic, since - * there is nothing to prevent an interrupt handler (that runs - * after setting panic_cpu) from invoking panic() again. + * from deadlocking the first cpu that invokes the panic, since there + * is nothing to prevent an interrupt handler (that runs after setting + * panic_cpu) from invoking panic() again. Also disables preemption + * here - notice it's not safe to rely on interrupt disabling to avoid + * preemption, since any cond_resched() or cond_resched_lock() might + * trigger a reschedule if the preempt count is 0 (for reference, see + * Documentation/locking/preempt-locking.rst). Some functions called + * from here want preempt disabled, so no point enabling it later. */ local_irq_disable(); preempt_disable_notrace(); /* - * It's possible to come here directly from a panic-assertion and - * not have preempt disabled. Some functions called from here want - * preempt to be disabled. No point enabling it later though... - * * Only one CPU is allowed to execute the panic code from here. For * multiple parallel invocations of panic, all other CPUs either * stop themself or will wait until they are stopped by the 1st CPU @@ -266,73 +381,75 @@ void panic(const char *fmt, ...) kgdb_panic(buf); /* - * If we have crashed and we have a crash kernel loaded let it handle - * everything else. - * If we want to run this after calling panic_notifiers, pass - * the "crash_kexec_post_notifiers" option to the kernel. + * Here lies one of the most subtle parts of the panic path, + * the panic notifiers and their order with regards to kdump. + * We currently have 4 sets of notifiers: * - * Bypass the panic_cpu check and call __crash_kexec directly. + * - the hypervisor list is composed by callbacks that are related + * to warn the FW / hypervisor about panic, or non-invasive LED + * controlling functions - (hopefully) low-risk for kdump, should + * run early if possible. + * + * - the informational list is composed by functions dumping data + * like kernel offsets, device error registers or tracing buffer; + * also log flooding prevention callbacks fit in this list. It is + * relatively safe to run before kdump. + * + * - the pre_reboot list basically is everything else, all the + * callbacks that don't fit in the 2 previous lists. It should + * run *after* kdump if possible, as it contains high-risk + * functions that may break kdump. + * + * - we also have a 4th list of notifiers, the post_reboot + * callbacks. This is not strongly related to kdump since it's + * always executed late in the panic path, after the restart + * mechanism (if set); its goal is to provide a way for + * architecture code effectively power-off/disable the system. + * + * The kernel provides the "panic_notifiers_level" parameter + * to adjust the ordering in which these notifiers should run + * with regards to kdump - the default level is 2, so both the + * hypervisor and informational notifiers should execute before + * the __crash_kexec(); the info notifier won't run by default + * unless there's some kmsg_dumper() registered. For details + * about it, check Documentation/admin-guide/kernel-parameters.txt. + * + * Notice that the code relies in bits set/clear operations to + * determine the ordering, functions *_once() execute only one + * time, as their name implies. The goal is to prevent too much + * if conditionals and more confusion. Finally, regarding CPUs + * disabling: unless NO panic notifier executes before kdump, + * we always disable secondary CPUs before __crash_kexec() and + * the notifiers execute. */ - if (!_crash_kexec_post_notifiers) { + order_panic_notifiers_and_kdump(); + + /* If no level, we should kdump ASAP. */ + if (!panic_notifiers_level) __crash_kexec(NULL); - /* - * Note smp_send_stop is the usual smp shutdown function, which - * unfortunately means it may not be hardened to work in a - * panic situation. - */ - smp_send_stop(); - } else { - /* - * If we want to do crash dump after notifier calls and - * kmsg_dump, we will need architecture dependent extra - * works in addition to stopping other CPUs. - */ - crash_smp_send_stop(); - } + crash_smp_send_stop(); + panic_notifier_hypervisor_once(buf); - /* - * Run any panic handlers, including those that might need to - * add information to the kmsg dump output. - */ - atomic_notifier_call_chain(&panic_hypervisor_list, PANIC_NOTIFIER, buf); - atomic_notifier_call_chain(&panic_info_list, PANIC_NOTIFIER, buf); - atomic_notifier_call_chain(&panic_pre_reboot_list, PANIC_NOTIFIER, buf); + if (panic_notifier_info_once(buf)) { + panic_print_sys_info(false); + kmsg_dump(KMSG_DUMP_PANIC); + } - panic_print_sys_info(false); + panic_notifier_pre_reboot_once(buf); - kmsg_dump(KMSG_DUMP_PANIC); + __crash_kexec(NULL); - /* - * If you doubt kdump always works fine in any situation, - * "crash_kexec_post_notifiers" offers you a chance to run - * panic_notifiers and dumping kmsg before kdump. - * Note: since some panic_notifiers can make crashed kernel - * more unstable, it can increase risks of the kdump failure too. - * - * Bypass the panic_cpu check and call __crash_kexec directly. - */ - if (_crash_kexec_post_notifiers) - __crash_kexec(NULL); + panic_notifier_hypervisor_once(buf); -#ifdef CONFIG_VT - unblank_screen(); -#endif - console_unblank(); - - /* - * We may have ended up stopping the CPU holding the lock (in - * smp_send_stop()) while still having some valuable data in the console - * buffer. Try to acquire the lock then release it regardless of the - * result. The release will also print the buffers out. Locks debug - * should be disabled to avoid reporting bad unlock balance when - * panic() is not being callled from OOPS. - */ - debug_locks_off(); - console_flush_on_panic(CONSOLE_FLUSH_PENDING); + if (panic_notifier_info_once(buf)) { + panic_print_sys_info(false); + kmsg_dump(KMSG_DUMP_PANIC); + } - panic_print_sys_info(true); + panic_notifier_pre_reboot_once(buf); + console_flushing(); if (!panic_blink) panic_blink = no_blink; @@ -363,8 +480,7 @@ void panic(const char *fmt, ...) emergency_restart(); } - atomic_notifier_call_chain(&panic_post_reboot_list, - PANIC_NOTIFIER, buf); + panic_notifier_post_reboot_once(buf); pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); @@ -383,6 +499,15 @@ void panic(const char *fmt, ...) EXPORT_SYMBOL(panic); +/* + * Helper used in the kexec code, to validate if any + * panic notifier is set to execute early, before kdump. + */ +inline bool panic_notifiers_before_kdump(void) +{ + return panic_notifiers_level || crash_kexec_post_notifiers; +} + /* * TAINT_FORCED_RMMOD could be a per-module flag but the module * is being removed anyway. @@ -692,6 +817,9 @@ core_param(panic, panic_timeout, int, 0644); core_param(panic_print, panic_print, ulong, 0644); core_param(pause_on_oops, pause_on_oops, int, 0644); core_param(panic_on_warn, panic_on_warn, int, 0644); +core_param(panic_notifiers_level, panic_notifiers_level, uint, 0644); + +/* DEPRECATED in favor of panic_notifiers_level */ core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); static int __init oops_setup(char *s) diff --git a/tools/testing/selftests/pstore/pstore_crash_test b/tools/testing/selftests/pstore/pstore_crash_test index 2a329bbb4aca..1e60ce4501aa 100755 --- a/tools/testing/selftests/pstore/pstore_crash_test +++ b/tools/testing/selftests/pstore/pstore_crash_test @@ -25,6 +25,7 @@ touch $REBOOT_FLAG sync # cause crash -# Note: If you use kdump and want to see kmesg-* files after reboot, you should -# specify 'crash_kexec_post_notifiers' in 1st kernel's cmdline. +# Note: If you use kdump and want to see kmsg-* files after reboot, you should +# be sure that the parameter "panic_notifiers_level" is more than '2' (the +# default value for this parameter is '2') in the first kernel's cmdline. echo c > /proc/sysrq-trigger From patchwork Wed Apr 27 22:49:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829756 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C934FC433F5 for ; Wed, 27 Apr 2022 23:02:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239774AbiD0XFa (ORCPT ); Wed, 27 Apr 2022 19:05:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229494AbiD0XDA (ORCPT ); Wed, 27 Apr 2022 19:03:00 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF7248D6B1; Wed, 27 Apr 2022 15:56:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=jkYRHw7XLP9WroKS48pjCKf8DZNXzuNJkBrmx0UcVRc=; b=fbM2Fu2zuIxXnRnSKiwEiLyyJe XagaY4Y4i5sW6+W+epTqREIZ/ICl1Xi2oNzNqYSLfAiAeujQhcD2J6BRDpwqIfpK1aYn9B4Gepnqm UXEPwRAoI9LiYlvqP9hTq72CQIYynMwPnO/khrMA9H8ZW9ZKFbbeWjtIm9rBmVgqZX/xUmom+B8xi QY1BWJZFFIiYDwppo949ykglLrpZKKBYxdtwbkyN1uybFrzpdjMmPjKvulL2l2aogMZ8iE6aJcjTZ GbdvguHg7iZbdZllsoe1PY/R6t06HkFNrymWUR1pYeoyB7ORK7qb8BLpbexkNshwnkf274e7nAB6M ydSnW7kQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqaG-0002Qg-Er; Thu, 28 Apr 2022 00:56:33 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 25/30] panic, printk: Add console flush parameter and convert panic_print to a notifier Date: Wed, 27 Apr 2022 19:49:19 -0300 Message-Id: <20220427224924.592546-26-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the parameter "panic_print" relies in a function called directly on panic path; one of the flags the users can set for panic_print triggers a console replay mechanism, to show the entire kernel log buffer (from the beginning) in a panic event. Two problems with that: the dual nature of the panic_print isn't really appropriate, the function was originally meant to allow users dumping system information on panic events, and was "overridden" to also force a console flush of the full kernel log buffer. It also turns the code a bit more complex and duplicate than it needs to be. This patch proposes 2 changes: first, we decouple panic_print from the console flushing mechanism, in the form of a new kernel core parameter (panic_console_replay); we kept the functionality on panic_print to avoid userspace breakage, although we comment in both code and documentation that this panic_print usage is deprecated. We converted panic_print function to a panic notifier too, adding it on the panic informational notifier list, executed as the final callback. This allows a more clear code and makes sense, as panic_print_sys_info() is really a panic-time only function. We also moved its code to kernel/printk.c, it seems to make more sense given it's related to printing stuff. Suggested-by: Petr Mladek Signed-off-by: Guilherme G. Piccoli --- .../admin-guide/kernel-parameters.txt | 12 +++- Documentation/admin-guide/sysctl/kernel.rst | 5 +- include/linux/console.h | 2 + include/linux/panic.h | 1 - include/linux/printk.h | 1 + kernel/panic.c | 51 +++------------ kernel/printk/printk.c | 62 +++++++++++++++++++ 7 files changed, 87 insertions(+), 47 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8d3524060ce3..c99da8b2b216 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3791,6 +3791,14 @@ timeout < 0: reboot immediately Format: + panic_console_replay + [KNL] Force a kernel log replay in the console on + panic event. Notice that there is already a flush + mechanism for pending messages; this option is meant + for users that wish to replay the *full* buffer. + It deprecates the bit 5 setting on "panic_print", + both having the same functionality. + panic_notifiers_level= [KNL] Set the panic notifiers execution order. Format: @@ -3825,12 +3833,14 @@ bit 2: print timer info bit 3: print locks info if CONFIG_LOCKDEP is on bit 4: print ftrace buffer - bit 5: print all printk messages in buffer + bit 5: print all printk messages in buffer (DEPRECATED) bit 6: print all CPUs backtrace (if available in the arch) *Be aware* that this option may print a _lot_ of lines, so there are risks of losing older messages in the log. Use this option carefully, maybe worth to setup a bigger log buffer with "log_buf_len" along with this. + Also, notice that bit 5 was deprecated in favor of the + parameter "panic_console_replay". panic_on_taint= Bitmask for conditionally calling panic() in add_taint() Format: [,nousertaint] diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 1144ea3229a3..17b293a0e566 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -763,10 +763,13 @@ bit 1 print system memory info bit 2 print timer info bit 3 print locks info if ``CONFIG_LOCKDEP`` is on bit 4 print ftrace buffer -bit 5 print all printk messages in buffer +bit 5 print all printk messages in buffer (DEPRECATED) bit 6 print all CPUs backtrace (if available in the arch) ===== ============================================ +Notice that bit 5 was deprecated in favor of kernel core parameter +"panic_console_replay" (see kernel-parameters.txt documentation). + So for example to print tasks and memory info on panic, user can:: echo 3 > /proc/sys/kernel/panic_print diff --git a/include/linux/console.h b/include/linux/console.h index 7cd758a4f44e..351c14f623ad 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -169,6 +169,8 @@ enum con_flush_mode { CONSOLE_REPLAY_ALL, }; +extern bool panic_console_replay; + extern int add_preferred_console(char *name, int idx, char *options); extern void register_console(struct console *); extern int unregister_console(struct console *); diff --git a/include/linux/panic.h b/include/linux/panic.h index f5844908a089..34175d0188d0 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -22,7 +22,6 @@ extern unsigned int sysctl_oops_all_cpu_backtrace; #endif /* CONFIG_SMP */ extern int panic_timeout; -extern unsigned long panic_print; extern int panic_on_oops; extern int panic_on_unrecovered_nmi; extern int panic_on_io_nmi; diff --git a/include/linux/printk.h b/include/linux/printk.h index 1522df223c0f..aee2e8ebd541 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -13,6 +13,7 @@ extern const char linux_banner[]; extern const char linux_proc_banner[]; +extern unsigned long panic_print; extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ #define PRINTK_MAX_SINGLE_HEADER_LEN 2 diff --git a/kernel/panic.c b/kernel/panic.c index b7c055d4f87f..ff257bd8f81b 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -68,15 +68,6 @@ unsigned int panic_notifiers_level = 2; /* DEPRECATED in favor of panic_notifiers_level */ bool crash_kexec_post_notifiers; -#define PANIC_PRINT_TASK_INFO 0x00000001 -#define PANIC_PRINT_MEM_INFO 0x00000002 -#define PANIC_PRINT_TIMER_INFO 0x00000004 -#define PANIC_PRINT_LOCK_INFO 0x00000008 -#define PANIC_PRINT_FTRACE_INFO 0x00000010 -#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 -#define PANIC_PRINT_ALL_CPU_BT 0x00000040 -unsigned long panic_print; - ATOMIC_NOTIFIER_HEAD(panic_hypervisor_list); EXPORT_SYMBOL(panic_hypervisor_list); @@ -168,33 +159,6 @@ void nmi_panic(struct pt_regs *regs, const char *msg) } EXPORT_SYMBOL(nmi_panic); -static void panic_print_sys_info(bool console_flush) -{ - if (console_flush) { - if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) - console_flush_on_panic(CONSOLE_REPLAY_ALL); - return; - } - - if (panic_print & PANIC_PRINT_ALL_CPU_BT) - trigger_all_cpu_backtrace(); - - if (panic_print & PANIC_PRINT_TASK_INFO) - show_state(); - - if (panic_print & PANIC_PRINT_MEM_INFO) - show_mem(0, NULL); - - if (panic_print & PANIC_PRINT_TIMER_INFO) - sysrq_timer_list_show(); - - if (panic_print & PANIC_PRINT_LOCK_INFO) - debug_show_all_locks(); - - if (panic_print & PANIC_PRINT_FTRACE_INFO) - ftrace_dump(DUMP_ALL); -} - /* * Helper that accumulates all console flushing routines executed on panic. */ @@ -218,7 +182,11 @@ static void console_flushing(void) debug_locks_off(); console_flush_on_panic(CONSOLE_FLUSH_PENDING); - panic_print_sys_info(true); + /* In case users wish to replay the full log buffer... */ + if (panic_console_replay) { + pr_warn("Replaying the log buffer from the beginning\n"); + console_flush_on_panic(CONSOLE_REPLAY_ALL); + } } #define PN_HYPERVISOR_BIT 0 @@ -431,10 +399,8 @@ void panic(const char *fmt, ...) crash_smp_send_stop(); panic_notifier_hypervisor_once(buf); - if (panic_notifier_info_once(buf)) { - panic_print_sys_info(false); + if (panic_notifier_info_once(buf)) kmsg_dump(KMSG_DUMP_PANIC); - } panic_notifier_pre_reboot_once(buf); @@ -442,10 +408,8 @@ void panic(const char *fmt, ...) panic_notifier_hypervisor_once(buf); - if (panic_notifier_info_once(buf)) { - panic_print_sys_info(false); + if (panic_notifier_info_once(buf)) kmsg_dump(KMSG_DUMP_PANIC); - } panic_notifier_pre_reboot_once(buf); @@ -814,7 +778,6 @@ EXPORT_SYMBOL(__stack_chk_fail); #endif core_param(panic, panic_timeout, int, 0644); -core_param(panic_print, panic_print, ulong, 0644); core_param(pause_on_oops, pause_on_oops, int, 0644); core_param(panic_on_warn, panic_on_warn, int, 0644); core_param(panic_notifiers_level, panic_notifiers_level, uint, 0644); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index e3a1c429fbbc..ad91d4c04246 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -3234,6 +3235,61 @@ void __init console_init(void) } } +#define PANIC_PRINT_TASK_INFO 0x00000001 +#define PANIC_PRINT_MEM_INFO 0x00000002 +#define PANIC_PRINT_TIMER_INFO 0x00000004 +#define PANIC_PRINT_LOCK_INFO 0x00000008 +#define PANIC_PRINT_FTRACE_INFO 0x00000010 + +/* DEPRECATED - please use "panic_console_replay" */ +#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 + +#define PANIC_PRINT_ALL_CPU_BT 0x00000040 + +unsigned long panic_print; +bool panic_console_replay; + +static int panic_print_sys_info(struct notifier_block *self, + unsigned long ev, void *unused) +{ + if (panic_print & PANIC_PRINT_ALL_CPU_BT) + trigger_all_cpu_backtrace(); + + if (panic_print & PANIC_PRINT_TASK_INFO) + show_state(); + + if (panic_print & PANIC_PRINT_MEM_INFO) + show_mem(0, NULL); + + if (panic_print & PANIC_PRINT_TIMER_INFO) + sysrq_timer_list_show(); + + if (panic_print & PANIC_PRINT_LOCK_INFO) + debug_show_all_locks(); + + if (panic_print & PANIC_PRINT_FTRACE_INFO) + ftrace_dump(DUMP_ALL); + + /* + * This is legacy/deprecated feature from panic_print, + * the console force flushing. We have now the parameter + * "panic_console_replay", but we need to keep the + * retro-compatibility with the old stuff... + */ + if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) + panic_console_replay = true; + + return NOTIFY_DONE; +} + +static struct notifier_block panic_print_nb = { + .notifier_call = panic_print_sys_info, + .priority = INT_MIN, /* defer to run as late as possible */ +}; + +core_param(panic_print, panic_print, ulong, 0644); +core_param(panic_console_replay, panic_console_replay, bool, 0644); + /* * Some boot consoles access data that is in the init section and which will * be discarded after the initcalls have been run. To make sure that no code @@ -3253,6 +3309,12 @@ static int __init printk_late_init(void) struct console *con; int ret; + /* + * Register the panic notifier to print user information + * in case the user have that set. + */ + atomic_notifier_chain_register(&panic_info_list, &panic_print_nb); + for_each_console(con) { if (!(con->flags & CON_BOOT)) continue; From patchwork Wed Apr 27 22:49:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829759 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A90FC433EF for ; Wed, 27 Apr 2022 23:02:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240036AbiD0XFg (ORCPT ); Wed, 27 Apr 2022 19:05:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240319AbiD0XEH (ORCPT ); Wed, 27 Apr 2022 19:04:07 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8AC692D24; Wed, 27 Apr 2022 15:57:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Vlo9T2/mvIa7VmsgTZAplfpKcY639xSpi9Lsc7QD2sA=; b=ZiYAT8sJyiBNaHzrk2673FL4+8 1oiyWalKP6LGmKEc9hZJWoXC6cS5nMMrcCw5Iicmmfaanay2XW+Ea9CLz93XJRZPptEPdWhd8bk0b rKw9muPDbsgcmhx+6dtX/C/iDyONNGYxGodf7FR5gZ6gaCx9CBSOMyg/WgkwloH6LwMYOPDHwMc9i DlZzPF1Rmfq/gUUioCECpXAnYQMmNjWP7xmmSjqLdHZxdMlvMlgrtO3h+d5FTnJJbisLeLao1OJx/ z7mwY9pmIo/3ja9SO2+rtPXIxKaESObUyZjm7eg6MS41mJJ7ZAlwRmPdpw93iK7tmvwyFHIvecdrE ZFlVRrJg==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqb3-0002Tm-Pi; Thu, 28 Apr 2022 00:57:22 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Andrea Parri , Dexuan Cui , Haiyang Zhang , "K. Y. Srinivasan" , Stephen Brennan , Stephen Hemminger , Tianyu Lan , Wei Liu Subject: [PATCH 26/30] Drivers: hv: Do not force all panic notifiers to execute before kdump Date: Wed, 27 Apr 2022 19:49:20 -0300 Message-Id: <20220427224924.592546-27-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Since commit a11589563e96 ("x86/Hyper-V: Report crash register data or kmsg before running crash kernel") Hyper-V forcibly sets the kernel parameter "crash_kexec_post_notifiers"; with that, it did enforce the execution of *all* panic notifiers before kdump. The main reason behind that is that Hyper-V has an hypervisor notification mechanism that has the ability of warning the hypervisor when the guest panics. Happens that after the panic notifiers refactor, we now have 3 lists and a level mechanism that defines the ordering of the notifiers execution with regards to kdump. And for Hyper-V, the specific notifier to inform the hypervisor about a panic lies in the first list, which *by default* is set to execute before kdump. Hence, this patch removes the hardcoded setting, effectively reverting the aforementioned commit. One of the problems with the forced approach was greatly exposed by commit d57d6fe5bf34 ("drivers: hv: log when enabling crash_kexec_post_notifiers") which ended-up confusing the user that didn't expect the notifiers to execute before kdump, since it's a user setting and wasn't enabled by such user. With the patch hereby proposed, that kind of issue doesn't happen anymore, the panic notifiers level is well-documented and users can expect a predictable behavior. Fixes: a11589563e96 ("x86/Hyper-V: Report crash register data or kmsg before running crash kernel") Fixes: d57d6fe5bf34 ("drivers: hv: log when enabling crash_kexec_post_notifiers" Cc: Andrea Parri (Microsoft) Cc: Dexuan Cui Cc: Haiyang Zhang Cc: "K. Y. Srinivasan" Cc: Michael Kelley Cc: Stephen Brennan Cc: Stephen Hemminger Cc: Tianyu Lan Cc: Wei Liu Tested-by: Fabio A M Martins Signed-off-by: Guilherme G. Piccoli --- Special thanks to Michael Kelley for the good information about the Hyper-V panic path in email threads some months ago, and to Fabio for the testing performed. drivers/hv/hv_common.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index ae68298c0dca..af59793de523 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -73,18 +73,6 @@ int __init hv_common_init(void) { int i; - /* - * Hyper-V expects to get crash register data or kmsg when - * crash enlightment is available and system crashes. Set - * crash_kexec_post_notifiers to be true to make sure that - * calling crash enlightment interface before running kdump - * kernel. - */ - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { - crash_kexec_post_notifiers = true; - pr_info("Hyper-V: enabling crash_kexec_post_notifiers\n"); - } - /* * Allocate the per-CPU state for the hypercall input arg. * If this allocation fails, we will not be able to setup From patchwork Wed Apr 27 22:49:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829758 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B91EC433F5 for ; Wed, 27 Apr 2022 23:02:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239884AbiD0XFf (ORCPT ); Wed, 27 Apr 2022 19:05:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240692AbiD0XES (ORCPT ); Wed, 27 Apr 2022 19:04:18 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 923C6B3DDD; Wed, 27 Apr 2022 15:57:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=C9iT/xJ8gF8J/f7SmqQO2c8pu+KvBPlFfkqGdYboS2I=; b=PMFgjQG40D4y0EE10+nqxAPHVI yNLZ1EZJdP0IH30iYafdBfM788VaINOAVfe8Gnevld0DclzQJRd8t+br/vJapdawGOEWHQTLdmHei 1IQvYGZ//MLpN+QQDVtOXWSfDQyyspNE1J3gOgOC4NUam3dGx8JeBgJ9jpYRHFoaP71Y3fG1ERN+7 JvwIb059Xf3lNBTrEP8JiyuPOh5ugwSvNao5NfaR+bMPV8BospKPkEU02jshVAtp1UBbOdjrRb2r2 ze90RIwfaZigyOQntmQCmXs163wt4gsMUWHmf1nSoidLeEjFKj9WA7H531Eyz4iqvzof4LvLiIP9u dq8Lxg9g==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqbL-0002UI-QD; Thu, 28 Apr 2022 00:57:40 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Benjamin Herrenschmidt , Hari Bathini , Michael Ellerman , Nicholas Piggin , Paul Mackerras Subject: [PATCH 27/30] powerpc: Do not force all panic notifiers to execute before kdump Date: Wed, 27 Apr 2022 19:49:21 -0300 Message-Id: <20220427224924.592546-28-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Commit 06e629c25daa ("powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic") introduced a hardcoded setting of kernel parameter "crash_kexec_post_notifiers", effectively forcing all the panic notifiers to execute earlier in the panic path, before kdump. The reason for that was a fadump issue on collecting data accurately, due to smp_send_stop() setting all CPUs offline, so the net effect desired with this change was to avoid calling the regular CPU shutdown function, and instead rely on crash_smp_send_stop(), which copes fine with fadump. The collateral effect was to increase the risk for kdump if fadump is not used, since it forces all panic notifiers to execute early, before kdump. Happens that, after a panic refactor, crash_smp_send_stop() is now used by default in the panic path, so there is no reason to mess with the notifiers ordering (which was also improved in the refactor) from within arch code. Fixes: 06e629c25daa ("powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic") Cc: Benjamin Herrenschmidt Cc: Hari Bathini Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul Mackerras Signed-off-by: Guilherme G. Piccoli --- We'd like to thanks specially the MiniCloud infrastructure [0] maintainers, that allow us to test PowerPC code in a very complete, functional and FREE environment. [0] https://openpower.ic.unicamp.br/minicloud arch/powerpc/kernel/fadump.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index 65562c4a0a69..35ae8c09af66 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -1649,14 +1649,6 @@ int __init setup_fadump(void) register_fadump(); } - /* - * In case of panic, fadump is triggered via ppc_panic_event() - * panic notifier. Setting crash_kexec_post_notifiers to 'true' - * lets panic() function take crash friendly path before panic - * notifiers are invoked. - */ - crash_kexec_post_notifiers = true; - return 1; } /* From patchwork Wed Apr 27 22:49:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829757 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AFACC4332F for ; Wed, 27 Apr 2022 23:02:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229973AbiD0XFb (ORCPT ); Wed, 27 Apr 2022 19:05:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241042AbiD0XEc (ORCPT ); Wed, 27 Apr 2022 19:04:32 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F576B6D00; Wed, 27 Apr 2022 15:58:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=jupyQNOg8qT8hQfxmdiNJNMjaTUz/u9LiRmSHTNez6Y=; b=p7drin3mWpI9T0ZfMOO6eJj4J8 Szpgonvq7i/v524yc5jBLpbigKUiUN0wy7/WDOnlytx03+FGgGN1Adqusl4cOO6PJlw+seakKl4N4 fX95EDE8pbxBc/NNWRr732wIqJtKKX/BphsJRWnwXH/62I6x/BTA0R4L8cWEa/lku3Ma0ky8B2K89 MQrzxBf2Hm8tnWC5d0fBkJ7uMzqRE/yfr9AAId6oRoN4APimw2mDpSMEi6ZVrVuwLoacCVsSTBNQz KQprHSNi9G6RdCXwUMjprlLz6QcEgqvhkAE50juvJF1BOQucBso5epBizOEqf+g5ZQam3KuAFn9x9 BasVHnnQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqbZ-0002Uv-Ai; Thu, 28 Apr 2022 00:57:53 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org Subject: [PATCH 28/30] panic: Unexport crash_kexec_post_notifiers Date: Wed, 27 Apr 2022 19:49:22 -0300 Message-Id: <20220427224924.592546-29-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org There is no users anymore of this variable that requires it to be "exported" in the headers; also, it was deprecated by the kernel parameter "panic_notifiers_level". Signed-off-by: Guilherme G. Piccoli --- include/linux/panic.h | 2 -- include/linux/panic_notifier.h | 1 - 2 files changed, 3 deletions(-) diff --git a/include/linux/panic.h b/include/linux/panic.h index 34175d0188d0..d301db07a8af 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -34,8 +34,6 @@ extern int sysctl_panic_on_rcu_stall; extern int sysctl_max_rcu_stall_to_panic; extern int sysctl_panic_on_stackoverflow; -extern bool crash_kexec_post_notifiers; - /* * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It * holds a CPU number which is executing panic() currently. A value of diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index b5041132321d..8fda7045e2f7 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -11,7 +11,6 @@ extern struct atomic_notifier_head panic_pre_reboot_list; extern struct atomic_notifier_head panic_post_reboot_list; bool panic_notifiers_before_kdump(void); -extern bool crash_kexec_post_notifiers; enum panic_notifier_val { PANIC_UNUSED, From patchwork Wed Apr 27 22:49:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829760 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BE42C433FE for ; Wed, 27 Apr 2022 23:02:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240054AbiD0XFk (ORCPT ); Wed, 27 Apr 2022 19:05:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241328AbiD0XEo (ORCPT ); Wed, 27 Apr 2022 19:04:44 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C099B53C2; Wed, 27 Apr 2022 15:58:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=1b6nDa/yJFcG5pUH/mG+iUzFXWwemhBkCT22/YaOiO0=; b=IjS2asgso9SNyNWZZrj9YMv/6F 3eZOrVvzgLxKKIoWELAWIZ9Y/f7MmYlHtb0XsZyDOudfDUF9WfHu+qH6xY14Mwj7EyQY5AwmQNe6v QY9uiwZxhZ2WIvN3bSO5hXV0+d77+K43N8ixpf942Orfv5mroywKkDY+GQFZJrgwqxcot4GD1q5St xIFh8Z0iJkBMhioashEH7Fwugdlgq5hENhZTnH6U/1cjnuHRdJ6m3FerTWr+GWqdP086mvnqcs/YS tVMBMJxDz0U3rAU8T7vP+Z25rbMa7jiyVQO7/s07AaONn+Kin25YyTFL/3tub+/wmWut7UZN8xzJW BauGVfjA==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqcA-0002Wy-Ov; Thu, 28 Apr 2022 00:58:31 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Benjamin Herrenschmidt , Hari Bathini , Michael Ellerman , Nicholas Piggin , Paul Mackerras Subject: [PATCH 29/30] powerpc: ps3, pseries: Avoid duplicate call to kmsg_dump() on panic Date: Wed, 27 Apr 2022 19:49:23 -0300 Message-Id: <20220427224924.592546-30-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently both pseries and ps3 are platforms that define special panic notifiers that run as callbacks inside powerpc generic panic notifier. In both cases kmsg_dump() is called, and the reason seems to be that both of these callbacks aims to effectively stop the machine, so nothing would execute after that - hence, both force a series of console flushing related operations, after calling the kmsg dumpers. Happens that recently the panic path was refactored, and now kmsg_dump() is *certainly* called before the pre_reboot panic notifiers, category in which both pseries/ps3 callbacks belong. In other words: kmsg_dump() will execute twice in both platforms, on panic path. This patch prevents that by disabling the kmsg_dump() for both platform's notifiers. But worth to notice that PowerNV still has a legit use for executing kmsg_dump() in its unrecoverable error path, so we rely in parameter passing to differentiate both cases. Also, since the pre_reboot notifiers still run earlier than console flushing routines, we kept that for both pseries and ps3 platforms, only skipping kmsg_dump(). Fixes: 35adacd6fc48 ("powerpc/pseries, ps3: panic flush kernel messages before halting system") Cc: Benjamin Herrenschmidt Cc: Hari Bathini Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul Mackerras Signed-off-by: Guilherme G. Piccoli --- We'd like to thanks specially the MiniCloud infrastructure [0] maintainers, that allow us to test PowerPC code in a very complete, functional and FREE environment. [0] https://openpower.ic.unicamp.br/minicloud arch/powerpc/include/asm/bug.h | 2 +- arch/powerpc/kernel/traps.c | 6 ++++-- arch/powerpc/platforms/powernv/opal.c | 2 +- arch/powerpc/platforms/ps3/setup.c | 2 +- arch/powerpc/platforms/pseries/setup.c | 2 +- 5 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index ecbae1832de3..49e5f6f86869 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -166,7 +166,7 @@ extern void die(const char *, struct pt_regs *, long); void die_mce(const char *str, struct pt_regs *regs, long err); extern bool die_will_crash(void); extern void panic_flush_kmsg_start(void); -extern void panic_flush_kmsg_end(void); +extern void panic_flush_kmsg_end(bool dump); #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index a08bb7cefdc5..837a5ed98d62 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -169,9 +169,11 @@ extern void panic_flush_kmsg_start(void) bust_spinlocks(1); } -extern void panic_flush_kmsg_end(void) +extern void panic_flush_kmsg_end(bool dump) { - kmsg_dump(KMSG_DUMP_PANIC); + if (dump) + kmsg_dump(KMSG_DUMP_PANIC); + bust_spinlocks(0); debug_locks_off(); console_flush_on_panic(CONSOLE_FLUSH_PENDING); diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c index 55a8fbfdb5b2..d172ceedece2 100644 --- a/arch/powerpc/platforms/powernv/opal.c +++ b/arch/powerpc/platforms/powernv/opal.c @@ -641,7 +641,7 @@ void __noreturn pnv_platform_error_reboot(struct pt_regs *regs, const char *msg) show_regs(regs); smp_send_stop(); - panic_flush_kmsg_end(); + panic_flush_kmsg_end(true); /* * Don't bother to shut things down because this will diff --git a/arch/powerpc/platforms/ps3/setup.c b/arch/powerpc/platforms/ps3/setup.c index 3de9145c20bc..7cb78e508fb3 100644 --- a/arch/powerpc/platforms/ps3/setup.c +++ b/arch/powerpc/platforms/ps3/setup.c @@ -102,7 +102,7 @@ static void ps3_panic(char *str) printk(" System does not reboot automatically.\n"); printk(" Please press POWER button.\n"); printk("\n"); - panic_flush_kmsg_end(); + panic_flush_kmsg_end(false); while(1) lv1_pause(1); diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 955ff8aa1644..d6eea473eafd 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -856,7 +856,7 @@ static void __init pSeries_setup_arch(void) static void pseries_panic(char *str) { - panic_flush_kmsg_end(); + panic_flush_kmsg_end(false); rtas_os_term(str); } From patchwork Wed Apr 27 22:49:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Guilherme G. Piccoli" X-Patchwork-Id: 12829761 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAEC2C4167D for ; Wed, 27 Apr 2022 23:02:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239793AbiD0XF4 (ORCPT ); Wed, 27 Apr 2022 19:05:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241467AbiD0XEt (ORCPT ); Wed, 27 Apr 2022 19:04:49 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A83CB6478; Wed, 27 Apr 2022 15:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=hhYlsUbOeU+dOwRnxPZPUYbOytvtm3s9TOl//oHNJDA=; b=d0jf6vbMLbNOzh0eGG9B6/Px+6 qkEUtrYepm4ucy/4pLos0iQRqgjXbtzxxFn26kSmjojOKmseLi3xGvVq3y13qqT30NTY0kTvl6DKc b6KKl04amU0+oieZ13497T1EMR69awT+qjyjGwR4D5aTKq4vZpRUj+GzWZO2UZDfeYATrEMziknBs TEMzSmzx206U+K28hnKwrx3+IjpI8ZztfEqS39tmb441zpVb+KuDwyZTgdwShziC74jYqn49bnQHG y/bSqJ0agKp8q0sRXPRW98dnPCHObluazUbKWH8Sqc1S7wQ8dewAG//hvPY5MrIv8zVHDor3/GUxI SaUMFP1g==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqcO-0002Xa-TN; Thu, 28 Apr 2022 00:58:45 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Anton Ivanov , Johannes Berg , Richard Weinberger Subject: [PATCH 30/30] um: Avoid duplicate call to kmsg_dump() Date: Wed, 27 Apr 2022 19:49:24 -0300 Message-Id: <20220427224924.592546-31-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Currently the panic notifier panic_exit() calls kmsg_dump() and some console flushing routines - this makes sense since such panic notifier exits UserMode Linux and never returns. Happens that after a panic refactor, kmsg_dump() is now always called *before* the pre_reboot list of panic notifiers, in which panic_exit() belongs, leading to a double call situation. This patch changes that by removing such call from the panic notifier, but leaving the console flushing calls since the pre_reboot list still runs before console flushing on panic(). Cc: Anton Ivanov Cc: Johannes Berg Cc: Richard Weinberger Signed-off-by: Guilherme G. Piccoli --- arch/um/kernel/um_arch.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index fc6e443299da..651310e3e86f 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -241,7 +241,6 @@ static void __init uml_postsetup(void) static int panic_exit(struct notifier_block *self, unsigned long unused1, void *unused2) { - kmsg_dump(KMSG_DUMP_PANIC); bust_spinlocks(1); bust_spinlocks(0); uml_exitcode = 1;