From patchwork Tue Sep 24 07:43:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: chenqiwu X-Patchwork-Id: 13810452 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E224CF9C6B for ; Tue, 24 Sep 2024 07:52:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=EBOy5gHyOhd9AM3jz7ucr3vlokWJoL7EJVNAm9AjtjA=; b=19OXy4R16wR1qfQbw53pR159Q6 6htxEVX5D+Tbxto00CGRN1b15kAPuWi9+akejCJ9NXFlo7A/sbFqfg61BznjmZPngm2wobBYycgdw VT1hwKlX0X93+rziBhfQ1G3+wF9HuCY2n4QD7xNivhUk7X6lRqdoo0fiXQNhXM+KbIduzxx8G7+F2 5br9ihZI7ElYELJlx+n3Aa+NO5Pk91yZp+el6xhQS2nNv8imTFE3iiDznT33bp63jCo3llSgVd4Ck 4oq2SV2wqVsEa8lmf/vqJQbEK/pzCGr5R+KJFURfSA8/Fhv0+Vx5a+nOHUUN68ieoY3p7WJgvhXzZ 7RQBaGhA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1st0Ld-00000001Uet-2XsL; Tue, 24 Sep 2024 07:52:37 +0000 Received: from mail-oa1-x2c.google.com ([2001:4860:4864:20::2c]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1st0DA-00000001T4Z-3BUW for linux-arm-kernel@lists.infradead.org; Tue, 24 Sep 2024 07:43:54 +0000 Received: by mail-oa1-x2c.google.com with SMTP id 586e51a60fabf-27b7a1480bdso2358978fac.2 for ; Tue, 24 Sep 2024 00:43:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727163831; x=1727768631; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=EBOy5gHyOhd9AM3jz7ucr3vlokWJoL7EJVNAm9AjtjA=; b=MCLdZalwB4ZphpK43+PZ8YLnpWd+onchBsCE5Bg3ZsPMAkL97W+lkF/yjOZsGTYSfC +h8BbDkD+oXIqWWtjMcizjjyQ418kbdadDIyQA9BWVjQ1M3uz7wTEvCS8oT42pUFnqVs 3ebexQcY8UtKwDKqgorqwW2KFW+ZrydKskiF3NM5cTIKeSQzAlCIB8D2Tcyc6Sx3B4sx VVJ1DKMCO3FStbMNCn7nvCKnQqjrFgB14t9KVIMVcF0M35dD864ZPv+urv0ka2VAJIRs A2sAa5d9yk1ei2VWZKDkjXEjNmu8Ysp6XpnJTMcQiKGVfPZtB/LYSRZZZ7JhIM0JrZdz ytzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727163831; x=1727768631; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=EBOy5gHyOhd9AM3jz7ucr3vlokWJoL7EJVNAm9AjtjA=; b=JCDiR+dJZHq7dq76KEjLLHXQAwnRmJV9lonOd67NOAuasCoyYS35bXE0TeSLQBVVxj orFzGLgPHHBJa3XyRjBbPR0mKkACowoj0JBdeDjQJUFeaKoBjgLPnB24VG/IQqTBIWzc /dUFmL2B9pUvUmldC6of2A5KLFX5fSAT9DmsH36rWZ45eFRtMtpOcqYhwv20cEFpPTG9 /I+dPtMEQ7rB3q08fqPDxpZy2KNdkcOYrUyW0vrlGzzpGQbDlyo98Ra7fryMzx3Kdn/3 EKvIhT4QBcWPxqlM7N7RilWZy1Y+Z2hANChm0YYHUWQyrB5fUbvRy4qRxGgwnnkrQ2XG zOzQ== X-Gm-Message-State: AOJu0YyXPJ+KZEUP5d1TP03G/I5ZZTOqBZ18M6yuL3aVwZbQa0u7mMuf Ujj4cn9joVQeq1KtcL+qWXICyuYbk7YaapzO1uxWlpV2QjrYMs1B X-Google-Smtp-Source: AGHT+IEwmYtWB4OJ9uArL7Pv98Nt18qw/HYsz/16ZW/TpgqyPm3+JqwY23fcghDaSlU60D/3uBKENw== X-Received: by 2002:a05:6870:468e:b0:277:f2d5:7834 with SMTP id 586e51a60fabf-2803a5d85a6mr9223888fac.14.1727163827396; Tue, 24 Sep 2024 00:43:47 -0700 (PDT) Received: from localhost ([183.226.245.34]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71afc97c17fsm690074b3a.152.2024.09.24.00.43.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Sep 2024 00:43:46 -0700 (PDT) From: "qiwu.chen" X-Google-Original-From: "qiwu.chen" To: corbet@lwn.net, oleg@redhat.com, catalin.marinas@arm.com, will@kernel.org, paulmck@kernel.org, akpm@linux-foundation.org Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, "qiwu.chen" Subject: [PATCH v4 1/2] panic: add option to dump task maps info in panic_print Date: Tue, 24 Sep 2024 15:43:40 +0800 Message-Id: <20240924074341.37272-1-qiwu.chen@transsion.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240924_004352_821984_2ADC459B X-CRM114-Status: GOOD ( 20.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Currently, it's hard to debug panic issues caused by kill init, since there is no debug info from user mode in current panic msg such as the user_regs and maps info. This patch adds an option to dump task maps info in panic_print. - changes history: v3: https://lore.kernel.org/all/20240922095504.7182-1-qiwu.chen@transsion.com/ https://lore.kernel.org/all/20240922095504.7182-2-qiwu.chen@transsion.com/ v2: https://lore.kernel.org/all/20231110031553.33186-1-qiwu.chen@transsion.com/ v1: https://lore.kernel.org/all/20231110022720.GA3087@rlk/ Signed-off-by: qiwu.chen --- .../admin-guide/kernel-parameters.txt | 1 + Documentation/admin-guide/sysctl/kernel.rst | 1 + fs/proc/task_mmu.c | 3 +- include/linux/mm.h | 4 ++ kernel/panic.c | 52 +++++++++++++++++++ 5 files changed, 60 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8337d0fed311..f76709deef6c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4253,6 +4253,7 @@ bit 5: print all printk messages in buffer bit 6: print all CPUs backtrace (if available in the arch) bit 7: print only tasks in uninterruptible (blocked) state + bit 8: print task maps info *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 diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index f8bc1630eba0..558e365b76a9 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -872,6 +872,7 @@ bit 4 print ftrace buffer bit 5 print all printk messages in buffer bit 6 print all CPUs backtrace (if available in the arch) bit 7 print only tasks in uninterruptible (blocked) state +bit 8 print task maps info ===== ============================================ So for example to print tasks and memory info on panic, user can:: diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index ade74a396968..37169ae36542 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -240,7 +240,7 @@ static int do_maps_open(struct inode *inode, struct file *file, sizeof(struct proc_maps_private)); } -static void get_vma_name(struct vm_area_struct *vma, +void get_vma_name(struct vm_area_struct *vma, const struct path **path, const char **name, const char **name_fmt) @@ -300,6 +300,7 @@ static void get_vma_name(struct vm_area_struct *vma, return; } } +EXPORT_SYMBOL(get_vma_name); static void show_vma_header_prefix(struct seq_file *m, unsigned long start, unsigned long end, diff --git a/include/linux/mm.h b/include/linux/mm.h index 13bff7cf03b7..2fa403aae1de 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3566,6 +3566,10 @@ static inline bool range_in_vma(struct vm_area_struct *vma, #ifdef CONFIG_MMU pgprot_t vm_get_page_prot(unsigned long vm_flags); void vma_set_page_prot(struct vm_area_struct *vma); +void get_vma_name(struct vm_area_struct *vma, + const struct path **path, + const char **name, + const char **name_fmt); #else static inline pgprot_t vm_get_page_prot(unsigned long vm_flags) { diff --git a/kernel/panic.c b/kernel/panic.c index 753d12f4dc8f..2217e1d0ad44 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -77,6 +77,8 @@ EXPORT_SYMBOL_GPL(panic_timeout); #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 #define PANIC_PRINT_ALL_CPU_BT 0x00000040 #define PANIC_PRINT_BLOCKED_TASKS 0x00000080 +#define PANIC_PRINT_TASK_MAPS_INFO 0x00000100 + unsigned long panic_print; ATOMIC_NOTIFIER_HEAD(panic_notifier_list); @@ -208,6 +210,53 @@ void nmi_panic(struct pt_regs *regs, const char *msg) } EXPORT_SYMBOL(nmi_panic); +/* + * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO + * flag is specified in panic_print, which is helpful to debug panic issues due + * to an unhandled falut in user mode such as kill init. + */ +static void dump_task_maps_info(struct task_struct *tsk) +{ + struct pt_regs *user_ret = task_pt_regs(tsk); + struct mm_struct *mm = tsk->mm; + struct vm_area_struct *vma; + + if (!mm || !user_mode(user_ret)) + return; + + pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk)); + mmap_read_lock(mm); + VMA_ITERATOR(vmi, mm, 0); + for_each_vma(vmi, vma) { + int flags = vma->vm_flags; + unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; + const struct path *path; + const char *name_fmt, *name; + char name_buf[SZ_256]; + + get_vma_name(vma, &path, &name, &name_fmt); + if (path) { + name = d_path(path, name_buf, sizeof(name_buf)); + name = IS_ERR(name) ? "?" : name; + } else if (name || name_fmt) { + snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name); + name = name_buf; + } + + if (name) + pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n", + vma->vm_start, vma->vm_end, + flags & VM_READ ? 'r' : '-', + flags & VM_WRITE ? 'w' : '-', + flags & VM_EXEC ? 'x' : '-', + flags & VM_MAYSHARE ? 's' : 'p', + pgoff, name); + + } + mmap_read_unlock(mm); + pr_info("Dump task %s:%d maps end\n", tsk->comm, task_pid_nr(tsk)); +} + static void panic_print_sys_info(bool console_flush) { if (console_flush) { @@ -233,6 +282,9 @@ static void panic_print_sys_info(bool console_flush) if (panic_print & PANIC_PRINT_BLOCKED_TASKS) show_state_filter(TASK_UNINTERRUPTIBLE); + + if (panic_print & PANIC_PRINT_TASK_MAPS_INFO) + dump_task_maps_info(current); } void check_panic_on_warn(const char *origin)