From patchwork Fri Oct 8 11:15:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545029 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75657C433F5 for ; Fri, 8 Oct 2021 11:19:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F02661038 for ; Fri, 8 Oct 2021 11:19:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240181AbhJHLTL (ORCPT ); Fri, 8 Oct 2021 07:19:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240082AbhJHLTK (ORCPT ); Fri, 8 Oct 2021 07:19:10 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A670DC061755; Fri, 8 Oct 2021 04:17:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=MLBczIwgfzeLbScljLp1G7yX9BxWvuTlFh8XrSH1m84=; b=EsWUcNy7X1pxSg/3JppKere+rn Q/LqgISmaCXx5XliS78/WHpuybOwDYcGnyg8+6zOCujnOENeS9MxMeI0yHF8ciMWwprpi106Oe0el 2FGvYJ9irJhyN/eRUfx5bNZbg2X84D6RGTQ92hMA7nIX4zTMDBbG3uzjfg5kJ6rOflry5KrOrbQbR +XkfJvP47dp0mtpF1+w5koEaA4Vg37N2fsHFA9qOnXWZ2/w6EmtF4Jlvd9qCGQpHy+Jn78ZXMT/MV yXgISXQUZsjInq3nql3MimkKotV3df/LVtiZdLns5caQAxkY/wCyfkBQUx6E5IM8URQIcB+MTLReu H8Cge1HA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYnsD-008eL9-Bp; Fri, 08 Oct 2021 11:17:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 04A87300F19; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id D20662C4B3CDC; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.090829198@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:28 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net, kernel test robot , stable@vger.kernel.org Subject: [PATCH 1/7] Revert "proc/wchan: use printk format instead of lookup_symbol_name()" References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Kees Cook This reverts commit 152c432b128cb043fc107e8f211195fe94b2159c. When a kernel address couldn't be symbolized for /proc/$pid/wchan, it would leak the raw value, a potential information exposure. This is a regression compared to the safer pre-v5.12 behavior. Reported-by: kernel test robot Reported-by: Vito Caputo Reported-by: Jann Horn Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org --- fs/proc/base.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -67,6 +67,7 @@ #include #include #include +#include #include #include #include @@ -386,17 +387,19 @@ static int proc_pid_wchan(struct seq_fil struct pid *pid, struct task_struct *task) { unsigned long wchan; + char symname[KSYM_NAME_LEN]; - if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) - wchan = get_wchan(task); - else - wchan = 0; - - if (wchan) - seq_printf(m, "%ps", (void *) wchan); - else - seq_putc(m, '0'); + if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) + goto print0; + wchan = get_wchan(task); + if (wchan && !lookup_symbol_name(wchan, symname)) { + seq_puts(m, symname); + return 0; + } + +print0: + seq_putc(m, '0'); return 0; } #endif /* CONFIG_KALLSYMS */ From patchwork Fri Oct 8 11:15:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545031 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D2EFC433FE for ; Fri, 8 Oct 2021 11:19:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 665E461038 for ; Fri, 8 Oct 2021 11:19:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240180AbhJHLVa (ORCPT ); Fri, 8 Oct 2021 07:21:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240238AbhJHLT3 (ORCPT ); Fri, 8 Oct 2021 07:19:29 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0449C061570; 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Fri, 8 Oct 2021 13:17:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id D699F2DB84A66; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.151570317@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:29 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 2/7] leaking_addresses: Always print a trailing newline References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Kees Cook For files that lack trailing newlines and match a leaking address (e.g. wchan[1]), the leaking_addresses.pl report would run together with the next line, making things look corrupted. Unconditionally remove the newline on input, and write it back out on output. [1] https://lore.kernel.org/all/20210103142726.GC30643@xsang-OptiPlex-9020/ Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) --- scripts/leaking_addresses.pl | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/scripts/leaking_addresses.pl +++ b/scripts/leaking_addresses.pl @@ -455,8 +455,9 @@ sub parse_file open my $fh, "<", $file or return; while ( <$fh> ) { + chomp; if (may_leak_address($_)) { - print $file . ': ' . $_; + printf("$file: $_\n"); } } close $fh; From patchwork Fri Oct 8 11:15:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545015 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F03DC433EF for ; Fri, 8 Oct 2021 11:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39C7961038 for ; Fri, 8 Oct 2021 11:17:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240128AbhJHLTK (ORCPT ); Fri, 8 Oct 2021 07:19:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240084AbhJHLTK (ORCPT ); Fri, 8 Oct 2021 07:19:10 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A64DBC061570; Fri, 8 Oct 2021 04:17:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=Wpos95iylg095UsnNd0rlORwCu4Pilf9lSCl83VJs5E=; b=D5gn/w+kAJPRW9syBZ6bNLF5jH TihRX03GgyxgNzl+IwjDIV5wSjEiKKF3sVGg3I89GlGxXeb3qS+b5clklyCbFOW3VOMc8JIrpLNw0 Kedl++F7FhITDTvd8Ycsam6Xip+7Nog8MZ7VGvSTN+raC5xQ3WYEgnCP2XFgX9xuBQ2zwDpr/j0fg OwatR0nCMo18uKPaA5Eb9+jY0NsUubllEyo3a1mdCN6gm3kzd1vw05cbSXqXHNQ1NprLCl40lncS2 vxP5kEnMb5SJmzxtYZHA61gWgRoaaS/68hioT5a17e8YgAEHz+8ZyAwsHZAfPSE3mlIJIPbcOIo4P khD6vjtg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYnsD-008eLB-AA; Fri, 08 Oct 2021 11:17:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 99013302A2C; Fri, 8 Oct 2021 13:17:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id DAF102DB84A68; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.211281780@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:30 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 3/7] proc: Use task_is_running() for wchan in /proc/$pid/stat References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Kees Cook The implementations of get_wchan() can be expensive. The only information imparted here is whether or not a process is currently blocked in the scheduler (and even this doesn't need to be exact). Avoid doing the heavy lifting of stack walking and just report that information by using task_is_running(). Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) --- fs/proc/array.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -541,7 +541,7 @@ static int do_task_stat(struct seq_file } if (permitted && (!whole || num_threads < 2)) - wchan = get_wchan(task); + wchan = !task_is_running(task); if (!whole) { min_flt = task->min_flt; maj_flt = task->maj_flt; @@ -606,10 +606,7 @@ static int do_task_stat(struct seq_file * * This works with older implementations of procps as well. */ - if (wchan) - seq_puts(m, " 1"); - else - seq_puts(m, " 0"); + seq_put_decimal_ull(m, " ", wchan); seq_put_decimal_ull(m, " ", 0); seq_put_decimal_ull(m, " ", 0); From patchwork Fri Oct 8 11:15:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545017 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E1DAC433F5 for ; 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Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.271115116@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:31 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 4/7] x86: Fix get_wchan() to support the ORC unwinder References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Qi Zheng Currently, the kernel CONFIG_UNWINDER_ORC option is enabled by default on x86, but the implementation of get_wchan() is still based on the frame pointer unwinder, so the /proc//wchan usually returned 0 regardless of whether the task is running. Reimplement get_wchan() by calling stack_trace_save_tsk(), which is adapted to the ORC and frame pointer unwinders. Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Signed-off-by: Qi Zheng Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kernel/process.c | 51 ++-------------------------------------------- 1 file changed, 3 insertions(+), 48 deletions(-) --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -944,58 +944,13 @@ unsigned long arch_randomize_brk(struct */ unsigned long get_wchan(struct task_struct *p) { - unsigned long start, bottom, top, sp, fp, ip, ret = 0; - int count = 0; + unsigned long entry = 0; if (p == current || task_is_running(p)) return 0; - if (!try_get_task_stack(p)) - return 0; - - start = (unsigned long)task_stack_page(p); - if (!start) - goto out; - - /* - * Layout of the stack page: - * - * ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long) - * PADDING - * ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING - * stack - * ----------- bottom = start - * - * The tasks stack pointer points at the location where the - * framepointer is stored. The data on the stack is: - * ... IP FP ... IP FP - * - * We need to read FP and IP, so we need to adjust the upper - * bound by another unsigned long. - */ - top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING; - top -= 2 * sizeof(unsigned long); - bottom = start; - - sp = READ_ONCE(p->thread.sp); - if (sp < bottom || sp > top) - goto out; - - fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp); - do { - if (fp < bottom || fp > top) - goto out; - ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long))); - if (!in_sched_functions(ip)) { - ret = ip; - goto out; - } - fp = READ_ONCE_NOCHECK(*(unsigned long *)fp); - } while (count++ < 16 && !task_is_running(p)); - -out: - put_task_stack(p); - return ret; + stack_trace_save_tsk(p, &entry, 1, 0); + return entry; } long do_arch_prctl_common(struct task_struct *task, int option, From patchwork Fri Oct 8 11:15:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545021 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E7D6C433FE for ; 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Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.332092234@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:32 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 5/7] sched: Add wrapper for get_wchan() to keep task blocked References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org From: Kees Cook Having a stable wchan means the process must be blocked and for it to stay that way while performing stack unwinding. Suggested-by: Peter Zijlstra Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Acked-by: Geert Uytterhoeven Tested-by: Mark Rutland [arm64] Acked-by: Russell King (Oracle) [arm] --- arch/alpha/include/asm/processor.h | 2 +- arch/alpha/kernel/process.c | 5 ++--- arch/arc/include/asm/processor.h | 2 +- arch/arc/kernel/stacktrace.c | 4 ++-- arch/arm/include/asm/processor.h | 2 +- arch/arm/kernel/process.c | 4 +--- arch/arm64/include/asm/processor.h | 2 +- arch/arm64/kernel/process.c | 4 +--- arch/csky/include/asm/processor.h | 2 +- arch/csky/kernel/stacktrace.c | 5 ++--- arch/h8300/include/asm/processor.h | 2 +- arch/h8300/kernel/process.c | 5 +---- arch/hexagon/include/asm/processor.h | 2 +- arch/hexagon/kernel/process.c | 4 +--- arch/ia64/include/asm/processor.h | 2 +- arch/ia64/kernel/process.c | 5 +---- arch/m68k/include/asm/processor.h | 2 +- arch/m68k/kernel/process.c | 4 +--- arch/microblaze/include/asm/processor.h | 2 +- arch/microblaze/kernel/process.c | 2 +- arch/mips/include/asm/processor.h | 2 +- arch/mips/kernel/process.c | 8 +++----- arch/nds32/include/asm/processor.h | 2 +- arch/nds32/kernel/process.c | 7 +------ arch/nios2/include/asm/processor.h | 2 +- arch/nios2/kernel/process.c | 5 +---- arch/openrisc/include/asm/processor.h | 2 +- arch/openrisc/kernel/process.c | 2 +- arch/parisc/include/asm/processor.h | 2 +- arch/parisc/kernel/process.c | 5 +---- arch/powerpc/include/asm/processor.h | 2 +- arch/powerpc/kernel/process.c | 9 +++------ arch/riscv/include/asm/processor.h | 2 +- arch/riscv/kernel/stacktrace.c | 12 +++++------- arch/s390/include/asm/processor.h | 2 +- arch/s390/kernel/process.c | 4 ++-- arch/sh/include/asm/processor_32.h | 2 +- arch/sh/kernel/process_32.c | 5 +---- arch/sparc/include/asm/processor_32.h | 2 +- arch/sparc/include/asm/processor_64.h | 2 +- arch/sparc/kernel/process_32.c | 5 +---- arch/sparc/kernel/process_64.c | 5 +---- arch/um/include/asm/processor-generic.h | 2 +- arch/um/kernel/process.c | 5 +---- arch/x86/include/asm/processor.h | 2 +- arch/x86/kernel/process.c | 5 +---- arch/xtensa/include/asm/processor.h | 2 +- arch/xtensa/kernel/process.c | 5 +---- include/linux/sched.h | 1 + kernel/sched/core.c | 19 +++++++++++++++++++ 50 files changed, 80 insertions(+), 112 deletions(-) --- a/arch/alpha/include/asm/processor.h +++ b/arch/alpha/include/asm/processor.h @@ -42,7 +42,7 @@ extern void start_thread(struct pt_regs struct task_struct; extern void release_thread(struct task_struct *); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) --- a/arch/alpha/kernel/process.c +++ b/arch/alpha/kernel/process.c @@ -376,12 +376,11 @@ thread_saved_pc(struct task_struct *t) } unsigned long -get_wchan(struct task_struct *p) +__get_wchan(struct task_struct *p) { unsigned long schedule_frame; unsigned long pc; - if (!p || p == current || task_is_running(p)) - return 0; + /* * This one depends on the frame size of schedule(). Do a * "disass schedule" in gdb to find the frame size. Also, the --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -70,7 +70,7 @@ struct task_struct; extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp); -extern unsigned int get_wchan(struct task_struct *p); +extern unsigned int __get_wchan(struct task_struct *p); #endif /* !__ASSEMBLY__ */ --- a/arch/arc/kernel/stacktrace.c +++ b/arch/arc/kernel/stacktrace.c @@ -15,7 +15,7 @@ * = specifics of data structs where trace is saved(CONFIG_STACKTRACE etc) * * vineetg: March 2009 - * -Implemented correct versions of thread_saved_pc() and get_wchan() + * -Implemented correct versions of thread_saved_pc() and __get_wchan() * * rajeshwarr: 2008 * -Initial implementation @@ -248,7 +248,7 @@ void show_stack(struct task_struct *tsk, * Of course just returning schedule( ) would be pointless so unwind until * the function is not in schedular code */ -unsigned int get_wchan(struct task_struct *tsk) +unsigned int __get_wchan(struct task_struct *tsk) { return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL); } --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -84,7 +84,7 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1) --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -276,13 +276,11 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { struct stackframe frame; unsigned long stack_page; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; frame.fp = thread_saved_fp(p); frame.sp = thread_saved_sp(p); --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -257,7 +257,7 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); void update_sctlr_el1(u64 sctlr); --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -528,13 +528,11 @@ __notrace_funcgraph struct task_struct * return last; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { struct stackframe frame; unsigned long stack_page, ret = 0; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; stack_page = (unsigned long)try_get_task_stack(p); if (!stack_page) --- a/arch/csky/include/asm/processor.h +++ b/arch/csky/include/asm/processor.h @@ -81,7 +81,7 @@ static inline void release_thread(struct extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->usp) --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -111,12 +111,11 @@ static bool save_wchan(unsigned long pc, return false; } -unsigned long get_wchan(struct task_struct *task) +unsigned long __get_wchan(struct task_struct *task) { unsigned long pc = 0; - if (likely(task && task != current && !task_is_running(task))) - walk_stackframe(task, NULL, save_wchan, &pc); + walk_stackframe(task, NULL, save_wchan, &pc); return pc; } --- a/arch/h8300/include/asm/processor.h +++ b/arch/h8300/include/asm/processor.h @@ -105,7 +105,7 @@ static inline void release_thread(struct { } -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) \ ({ \ --- a/arch/h8300/kernel/process.c +++ b/arch/h8300/kernel/process.c @@ -128,15 +128,12 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long fp, pc; unsigned long stack_page; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - stack_page = (unsigned long)p; fp = ((struct pt_regs *)p->thread.ksp)->er6; do { --- a/arch/hexagon/include/asm/processor.h +++ b/arch/hexagon/include/asm/processor.h @@ -64,7 +64,7 @@ struct thread_struct { extern void release_thread(struct task_struct *dead_task); /* Get wait channel for task P. */ -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); /* The following stuff is pretty HEXAGON specific. */ --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -130,13 +130,11 @@ void flush_thread(void) * is an identification of the point at which the scheduler * was invoked by a blocked thread. */ -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long fp, pc; unsigned long stack_page; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; stack_page = (unsigned long)task_stack_page(p); fp = ((struct hexagon_switch_stack *)p->thread.switch_sp)->fp; --- a/arch/ia64/include/asm/processor.h +++ b/arch/ia64/include/asm/processor.h @@ -330,7 +330,7 @@ struct task_struct; #define release_thread(dead_task) /* Get wait channel for task P. */ -extern unsigned long get_wchan (struct task_struct *p); +extern unsigned long __get_wchan (struct task_struct *p); /* Return instruction pointer of blocked task TSK. */ #define KSTK_EIP(tsk) \ --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -523,15 +523,12 @@ exit_thread (struct task_struct *tsk) } unsigned long -get_wchan (struct task_struct *p) +__get_wchan (struct task_struct *p) { struct unw_frame_info info; unsigned long ip; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - /* * Note: p may not be a blocked task (it could be current or * another process running on some other CPU. Rather than --- a/arch/m68k/include/asm/processor.h +++ b/arch/m68k/include/asm/processor.h @@ -125,7 +125,7 @@ static inline void release_thread(struct { } -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) \ ({ \ --- a/arch/m68k/kernel/process.c +++ b/arch/m68k/kernel/process.c @@ -263,13 +263,11 @@ int dump_fpu (struct pt_regs *regs, stru } EXPORT_SYMBOL(dump_fpu); -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long fp, pc; unsigned long stack_page; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; stack_page = (unsigned long)task_stack_page(p); fp = ((struct switch_stack *)p->thread.ksp)->a6; --- a/arch/microblaze/include/asm/processor.h +++ b/arch/microblaze/include/asm/processor.h @@ -68,7 +68,7 @@ static inline void release_thread(struct { } -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); /* The size allocated for kernel stacks. This _must_ be a power of two! */ # define KERNEL_STACK_SIZE 0x2000 --- a/arch/microblaze/kernel/process.c +++ b/arch/microblaze/kernel/process.c @@ -112,7 +112,7 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { /* TBD (used by procfs) */ return 0; --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -369,7 +369,7 @@ static inline void flush_thread(void) { } -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \ THREAD_SIZE - 32 - sizeof(struct pt_regs)) --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -511,7 +511,7 @@ static int __init frame_info_init(void) /* * Without schedule() frame info, result given by - * thread_saved_pc() and get_wchan() are not reliable. + * thread_saved_pc() and __get_wchan() are not reliable. */ if (schedule_mfi.pc_offset < 0) printk("Can't analyze schedule() prologue at %p\n", schedule); @@ -652,9 +652,9 @@ unsigned long unwind_stack(struct task_s #endif /* - * get_wchan - a maintenance nightmare^W^Wpain in the ass ... + * __get_wchan - a maintenance nightmare^W^Wpain in the ass ... */ -unsigned long get_wchan(struct task_struct *task) +unsigned long __get_wchan(struct task_struct *task) { unsigned long pc = 0; #ifdef CONFIG_KALLSYMS @@ -662,8 +662,6 @@ unsigned long get_wchan(struct task_stru unsigned long ra = 0; #endif - if (!task || task == current || task_is_running(task)) - goto out; if (!task_stack_page(task)) goto out; --- a/arch/nds32/include/asm/processor.h +++ b/arch/nds32/include/asm/processor.h @@ -83,7 +83,7 @@ extern struct task_struct *last_task_use /* Prepare to copy thread state - unlazy all lazy status */ #define prepare_to_copy(tsk) do { } while (0) -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define cpu_relax() barrier() --- a/arch/nds32/kernel/process.c +++ b/arch/nds32/kernel/process.c @@ -233,15 +233,12 @@ int dump_fpu(struct pt_regs *regs, elf_f EXPORT_SYMBOL(dump_fpu); -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long fp, lr; unsigned long stack_start, stack_end; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - if (IS_ENABLED(CONFIG_FRAME_POINTER)) { stack_start = (unsigned long)end_of_stack(p); stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; @@ -258,5 +255,3 @@ unsigned long get_wchan(struct task_stru } return 0; } - -EXPORT_SYMBOL(get_wchan); --- a/arch/nios2/include/asm/processor.h +++ b/arch/nios2/include/asm/processor.h @@ -69,7 +69,7 @@ static inline void release_thread(struct { } -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1) --- a/arch/nios2/kernel/process.c +++ b/arch/nios2/kernel/process.c @@ -217,15 +217,12 @@ void dump(struct pt_regs *fp) pr_emerg("\n\n"); } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long fp, pc; unsigned long stack_page; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - stack_page = (unsigned long)p; fp = ((struct switch_stack *)p->thread.ksp)->fp; /* ;dgt2 */ do { --- a/arch/openrisc/include/asm/processor.h +++ b/arch/openrisc/include/asm/processor.h @@ -73,7 +73,7 @@ struct thread_struct { void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp); void release_thread(struct task_struct *); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define cpu_relax() barrier() --- a/arch/openrisc/kernel/process.c +++ b/arch/openrisc/kernel/process.c @@ -263,7 +263,7 @@ void dump_elf_thread(elf_greg_t *dest, s dest[35] = 0; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { /* TODO */ --- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -273,7 +273,7 @@ struct mm_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) ((tsk)->thread.regs.iaoq[0]) #define KSTK_ESP(tsk) ((tsk)->thread.regs.gr[30]) --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -240,15 +240,12 @@ copy_thread(unsigned long clone_flags, u } unsigned long -get_wchan(struct task_struct *p) +__get_wchan(struct task_struct *p) { struct unwind_frame_info info; unsigned long ip; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - /* * These bracket the sleeping functions.. */ --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -300,7 +300,7 @@ struct thread_struct { #define task_pt_regs(tsk) ((tsk)->thread.regs) -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0) #define KSTK_ESP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0) --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2111,14 +2111,11 @@ int validate_sp(unsigned long sp, struct EXPORT_SYMBOL(validate_sp); -static unsigned long __get_wchan(struct task_struct *p) +static unsigned long ___get_wchan(struct task_struct *p) { unsigned long ip, sp; int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - sp = p->thread.ksp; if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) return 0; @@ -2137,14 +2134,14 @@ static unsigned long __get_wchan(struct return 0; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long ret; if (!try_get_task_stack(p)) return 0; - ret = __get_wchan(p); + ret = ___get_wchan(p); put_task_stack(p); --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -66,7 +66,7 @@ static inline void release_thread(struct { } -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); static inline void wait_for_interrupt(void) --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -128,16 +128,14 @@ static bool save_wchan(void *arg, unsign return true; } -unsigned long get_wchan(struct task_struct *task) +unsigned long __get_wchan(struct task_struct *task) { unsigned long pc = 0; - if (likely(task && task != current && !task_is_running(task))) { - if (!try_get_task_stack(task)) - return 0; - walk_stackframe(task, NULL, save_wchan, &pc); - put_task_stack(task); - } + if (!try_get_task_stack(task)) + return 0; + walk_stackframe(task, NULL, save_wchan, &pc); + put_task_stack(task); return pc; } --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -192,7 +192,7 @@ static inline void release_thread(struct void guarded_storage_release(struct task_struct *tsk); void gs_load_bc_cb(struct pt_regs *regs); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); #define task_pt_regs(tsk) ((struct pt_regs *) \ (task_stack_page(tsk) + THREAD_SIZE) - 1) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->psw.addr) --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -181,12 +181,12 @@ void execve_tail(void) asm volatile("sfpc %0" : : "d" (0)); } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { struct unwind_state state; unsigned long ip = 0; - if (!p || p == current || task_is_running(p) || !task_stack_page(p)) + if (!task_stack_page(p)) return 0; if (!try_get_task_stack(p)) --- a/arch/sh/include/asm/processor_32.h +++ b/arch/sh/include/asm/processor_32.h @@ -180,7 +180,7 @@ static inline void show_code(struct pt_r } #endif -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[15]) --- a/arch/sh/kernel/process_32.c +++ b/arch/sh/kernel/process_32.c @@ -182,13 +182,10 @@ __switch_to(struct task_struct *prev, st return prev; } -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long pc; - if (!p || p == current || task_is_running(p)) - return 0; - /* * The same comment as on the Alpha applies here, too ... */ --- a/arch/sparc/include/asm/processor_32.h +++ b/arch/sparc/include/asm/processor_32.h @@ -89,7 +89,7 @@ static inline void start_thread(struct p /* Free all resources held by a thread. */ #define release_thread(tsk) do { } while(0) -unsigned long get_wchan(struct task_struct *); +unsigned long __get_wchan(struct task_struct *); #define task_pt_regs(tsk) ((tsk)->thread.kregs) #define KSTK_EIP(tsk) ((tsk)->thread.kregs->pc) --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -183,7 +183,7 @@ do { \ /* Free all resources held by a thread. */ #define release_thread(tsk) do { } while (0) -unsigned long get_wchan(struct task_struct *task); +unsigned long __get_wchan(struct task_struct *task); #define task_pt_regs(tsk) (task_thread_info(tsk)->kregs) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->tpc) --- a/arch/sparc/kernel/process_32.c +++ b/arch/sparc/kernel/process_32.c @@ -365,7 +365,7 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long get_wchan(struct task_struct *task) +unsigned long __get_wchan(struct task_struct *task) { unsigned long pc, fp, bias = 0; unsigned long task_base = (unsigned long) task; @@ -373,9 +373,6 @@ unsigned long get_wchan(struct task_stru struct reg_window32 *rw; int count = 0; - if (!task || task == current || task_is_running(task)) - goto out; - fp = task_thread_info(task)->ksp + bias; do { /* Bogus frame pointer? */ --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -663,7 +663,7 @@ int arch_dup_task_struct(struct task_str return 0; } -unsigned long get_wchan(struct task_struct *task) +unsigned long __get_wchan(struct task_struct *task) { unsigned long pc, fp, bias = 0; struct thread_info *tp; @@ -671,9 +671,6 @@ unsigned long get_wchan(struct task_stru unsigned long ret = 0; int count = 0; - if (!task || task == current || task_is_running(task)) - goto out; - tp = task_thread_info(task); bias = STACK_BIAS; fp = task_thread_info(task)->ksp + bias; --- a/arch/um/include/asm/processor-generic.h +++ b/arch/um/include/asm/processor-generic.h @@ -106,6 +106,6 @@ extern struct cpuinfo_um boot_cpu_data; #define cache_line_size() (boot_cpu_data.cache_alignment) #define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf) -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); #endif --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -364,14 +364,11 @@ unsigned long arch_align_stack(unsigned } #endif -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long stack_page, sp, ip; bool seen_sched = 0; - if ((p == NULL) || (p == current) || task_is_running(p)) - return 0; - stack_page = (unsigned long) task_stack_page(p); /* Bail if the process has no kernel stack for some reason */ if (stack_page == 0) --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -590,7 +590,7 @@ static inline void load_sp0(unsigned lon /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long get_wchan(struct task_struct *p); +unsigned long __get_wchan(struct task_struct *p); /* * Generic CPUID function --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -943,13 +943,10 @@ unsigned long arch_randomize_brk(struct * because the task might wake up and we might look at a stack * changing under us. */ -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long entry = 0; - if (p == current || task_is_running(p)) - return 0; - stack_trace_save_tsk(p, &entry, 1, 0); return entry; } --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -215,7 +215,7 @@ struct mm_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) -extern unsigned long get_wchan(struct task_struct *p); +extern unsigned long __get_wchan(struct task_struct *p); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -298,15 +298,12 @@ int copy_thread(unsigned long clone_flag * These bracket the sleeping functions.. */ -unsigned long get_wchan(struct task_struct *p) +unsigned long __get_wchan(struct task_struct *p) { unsigned long sp, pc; unsigned long stack_page = (unsigned long) task_stack_page(p); int count = 0; - if (!p || p == current || task_is_running(p)) - return 0; - sp = p->thread.sp; pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp); --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2139,6 +2139,7 @@ static inline void set_task_cpu(struct t #endif /* CONFIG_SMP */ extern bool sched_task_on_rq(struct task_struct *p); +extern unsigned long get_wchan(struct task_struct *p); /* * In order to reduce various lock holder preemption latencies provide an --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1962,6 +1962,25 @@ bool sched_task_on_rq(struct task_struct return task_on_rq_queued(p); } +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long ip = 0; + unsigned int state; + + if (!p || p == current) + return 0; + + /* Only get wchan if task is blocked and we can keep it that way. */ + raw_spin_lock_irq(&p->pi_lock); + state = READ_ONCE(p->__state); + smp_rmb(); /* see try_to_wake_up() */ + if (state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq) + ip = __get_wchan(p); + raw_spin_unlock_irq(&p->pi_lock); + + return ip; +} + static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags) { if (!(flags & ENQUEUE_NOCLOCK)) From patchwork Fri Oct 8 11:15:33 2021 Content-Type: text/plain; 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Fri, 8 Oct 2021 13:17:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id EC8112DB84A6B; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.392918519@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:33 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 6/7] arch: __get_wchan || STACKTRACE_SUPPORT References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org It's trivial to implement __get_wchan() with CONFIG_STACKTRACE Signed-off-by: Peter Zijlstra (Intel) --- arch/arc/include/asm/processor.h | 2 - arch/arc/kernel/stacktrace.c | 17 -------------- arch/arm/include/asm/processor.h | 2 - arch/arm/kernel/process.c | 22 ------------------- arch/arm64/include/asm/processor.h | 2 - arch/arm64/kernel/process.c | 26 ---------------------- arch/csky/include/asm/processor.h | 2 - arch/csky/kernel/stacktrace.c | 18 --------------- arch/hexagon/include/asm/processor.h | 3 -- arch/hexagon/kernel/process.c | 26 ---------------------- arch/ia64/include/asm/processor.h | 3 -- arch/ia64/kernel/process.c | 28 ------------------------ arch/microblaze/include/asm/processor.h | 2 - arch/microblaze/kernel/process.c | 6 ----- arch/mips/include/asm/processor.h | 2 - arch/mips/kernel/process.c | 27 ----------------------- arch/nds32/include/asm/processor.h | 2 - arch/nds32/kernel/process.c | 23 ------------------- arch/openrisc/include/asm/processor.h | 1 arch/openrisc/kernel/process.c | 6 ----- arch/parisc/include/asm/processor.h | 2 - arch/parisc/kernel/process.c | 24 -------------------- arch/powerpc/include/asm/processor.h | 2 - arch/powerpc/kernel/process.c | 37 -------------------------------- arch/riscv/include/asm/processor.h | 3 -- arch/riscv/kernel/stacktrace.c | 21 ------------------ arch/s390/include/asm/processor.h | 1 arch/s390/kernel/process.c | 29 ------------------------- arch/sh/include/asm/processor_32.h | 2 - arch/sh/kernel/process_32.c | 19 ---------------- arch/sparc/include/asm/processor_64.h | 2 - arch/sparc/kernel/process_64.c | 28 ------------------------ arch/um/include/asm/processor-generic.h | 1 arch/um/kernel/process.c | 32 --------------------------- arch/x86/include/asm/processor.h | 2 - arch/x86/kernel/process.c | 14 ------------ arch/xtensa/include/asm/processor.h | 2 - arch/xtensa/kernel/process.c | 29 ------------------------- kernel/sched/core.c | 15 ++++++++++++ lib/Kconfig.debug | 7 ------ 40 files changed, 16 insertions(+), 476 deletions(-) --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -70,8 +70,6 @@ struct task_struct; extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp); -extern unsigned int __get_wchan(struct task_struct *p); - #endif /* !__ASSEMBLY__ */ /* --- a/arch/arc/kernel/stacktrace.c +++ b/arch/arc/kernel/stacktrace.c @@ -217,14 +217,6 @@ static int __collect_all_but_sched(unsig #endif -static int __get_first_nonsched(unsigned int address, void *unused) -{ - if (in_sched_functions(address)) - return 0; - - return -1; -} - /*------------------------------------------------------------------------- * APIs expected by various kernel sub-systems *------------------------------------------------------------------------- @@ -244,15 +236,6 @@ void show_stack(struct task_struct *tsk, show_stacktrace(tsk, NULL, loglvl); } -/* Another API expected by schedular, shows up in "ps" as Wait Channel - * Of course just returning schedule( ) would be pointless so unwind until - * the function is not in schedular code - */ -unsigned int __get_wchan(struct task_struct *tsk) -{ - return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL); -} - #ifdef CONFIG_STACKTRACE /* --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -84,8 +84,6 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1) --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -276,28 +276,6 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long __get_wchan(struct task_struct *p) -{ - struct stackframe frame; - unsigned long stack_page; - int count = 0; - - frame.fp = thread_saved_fp(p); - frame.sp = thread_saved_sp(p); - frame.lr = 0; /* recovered from the stack */ - frame.pc = thread_saved_pc(p); - stack_page = (unsigned long)task_stack_page(p); - do { - if (frame.sp < stack_page || - frame.sp >= stack_page + THREAD_SIZE || - unwind_frame(&frame) < 0) - return 0; - if (!in_sched_functions(frame.pc)) - return frame.pc; - } while (count ++ < 16); - return 0; -} - #ifdef CONFIG_MMU #ifdef CONFIG_KUSER_HELPERS /* --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -257,8 +257,6 @@ struct task_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - void update_sctlr_el1(u64 sctlr); /* Thread switching */ --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -528,32 +528,6 @@ __notrace_funcgraph struct task_struct * return last; } -unsigned long __get_wchan(struct task_struct *p) -{ - struct stackframe frame; - unsigned long stack_page, ret = 0; - int count = 0; - - stack_page = (unsigned long)try_get_task_stack(p); - if (!stack_page) - return 0; - - start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p)); - - do { - if (unwind_frame(p, &frame)) - goto out; - if (!in_sched_functions(frame.pc)) { - ret = frame.pc; - goto out; - } - } while (count++ < 16); - -out: - put_task_stack(p); - return ret; -} - unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) --- a/arch/csky/include/asm/processor.h +++ b/arch/csky/include/asm/processor.h @@ -81,8 +81,6 @@ static inline void release_thread(struct extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); -unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->usp) --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -101,24 +101,6 @@ void show_stack(struct task_struct *task walk_stackframe(task, NULL, print_trace_address, (void *)loglvl); } -static bool save_wchan(unsigned long pc, void *arg) -{ - if (!in_sched_functions(pc)) { - unsigned long *p = arg; - *p = pc; - return true; - } - return false; -} - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; - - walk_stackframe(task, NULL, save_wchan, &pc); - return pc; -} - #ifdef CONFIG_STACKTRACE static bool __save_trace(unsigned long pc, void *arg, bool nosched) { --- a/arch/hexagon/include/asm/processor.h +++ b/arch/hexagon/include/asm/processor.h @@ -63,9 +63,6 @@ struct thread_struct { /* Free all resources held by a thread; defined in process.c */ extern void release_thread(struct task_struct *dead_task); -/* Get wait channel for task P. */ -extern unsigned long __get_wchan(struct task_struct *p); - /* The following stuff is pretty HEXAGON specific. */ /* This is really just here for __switch_to. --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -126,32 +126,6 @@ void flush_thread(void) } /* - * The "wait channel" terminology is archaic, but what we want - * is an identification of the point at which the scheduler - * was invoked by a blocked thread. - */ -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long fp, pc; - unsigned long stack_page; - int count = 0; - - stack_page = (unsigned long)task_stack_page(p); - fp = ((struct hexagon_switch_stack *)p->thread.switch_sp)->fp; - do { - if (fp < (stack_page + sizeof(struct thread_info)) || - fp >= (THREAD_SIZE - 8 + stack_page)) - return 0; - pc = ((unsigned long *)fp)[1]; - if (!in_sched_functions(pc)) - return pc; - fp = *(unsigned long *) fp; - } while (count++ < 16); - - return 0; -} - -/* * Called on the exit path of event entry; see vm_entry.S * * Interrupts will already be disabled. --- a/arch/ia64/include/asm/processor.h +++ b/arch/ia64/include/asm/processor.h @@ -329,9 +329,6 @@ struct task_struct; */ #define release_thread(dead_task) -/* Get wait channel for task P. */ -extern unsigned long __get_wchan (struct task_struct *p); - /* Return instruction pointer of blocked task TSK. */ #define KSTK_EIP(tsk) \ ({ \ --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -522,34 +522,6 @@ exit_thread (struct task_struct *tsk) ia64_drop_fpu(tsk); } -unsigned long -__get_wchan (struct task_struct *p) -{ - struct unw_frame_info info; - unsigned long ip; - int count = 0; - - /* - * Note: p may not be a blocked task (it could be current or - * another process running on some other CPU. Rather than - * trying to determine if p is really blocked, we just assume - * it's blocked and rely on the unwind routines to fail - * gracefully if the process wasn't really blocked after all. - * --davidm 99/12/15 - */ - unw_init_from_blocked_task(&info, p); - do { - if (task_is_running(p)) - return 0; - if (unw_unwind(&info) < 0) - return 0; - unw_get_ip(&info, &ip); - if (!in_sched_functions(ip)) - return ip; - } while (count++ < 16); - return 0; -} - void cpu_halt (void) { --- a/arch/microblaze/include/asm/processor.h +++ b/arch/microblaze/include/asm/processor.h @@ -68,8 +68,6 @@ static inline void release_thread(struct { } -unsigned long __get_wchan(struct task_struct *p); - /* The size allocated for kernel stacks. This _must_ be a power of two! */ # define KERNEL_STACK_SIZE 0x2000 --- a/arch/microblaze/kernel/process.c +++ b/arch/microblaze/kernel/process.c @@ -112,12 +112,6 @@ int copy_thread(unsigned long clone_flag return 0; } -unsigned long __get_wchan(struct task_struct *p) -{ -/* TBD (used by procfs) */ - return 0; -} - /* Set up a thread for executing a new program */ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) { --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -369,8 +369,6 @@ static inline void flush_thread(void) { } -unsigned long __get_wchan(struct task_struct *p); - #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \ THREAD_SIZE - 32 - sizeof(struct pt_regs)) #define task_pt_regs(tsk) ((struct pt_regs *)__KSTK_TOS(tsk)) --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -651,33 +651,6 @@ unsigned long unwind_stack(struct task_s } #endif -/* - * __get_wchan - a maintenance nightmare^W^Wpain in the ass ... - */ -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; -#ifdef CONFIG_KALLSYMS - unsigned long sp; - unsigned long ra = 0; -#endif - - if (!task_stack_page(task)) - goto out; - - pc = thread_saved_pc(task); - -#ifdef CONFIG_KALLSYMS - sp = task->thread.reg29 + schedule_mfi.frame_size; - - while (in_sched_functions(pc)) - pc = unwind_stack(task, &sp, pc, &ra); -#endif - -out: - return pc; -} - unsigned long mips_stack_top(void) { unsigned long top = TASK_SIZE & PAGE_MASK; --- a/arch/nds32/include/asm/processor.h +++ b/arch/nds32/include/asm/processor.h @@ -83,8 +83,6 @@ extern struct task_struct *last_task_use /* Prepare to copy thread state - unlazy all lazy status */ #define prepare_to_copy(tsk) do { } while (0) -unsigned long __get_wchan(struct task_struct *p); - #define cpu_relax() barrier() #define task_pt_regs(task) \ --- a/arch/nds32/kernel/process.c +++ b/arch/nds32/kernel/process.c @@ -232,26 +232,3 @@ int dump_fpu(struct pt_regs *regs, elf_f } EXPORT_SYMBOL(dump_fpu); - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long fp, lr; - unsigned long stack_start, stack_end; - int count = 0; - - if (IS_ENABLED(CONFIG_FRAME_POINTER)) { - stack_start = (unsigned long)end_of_stack(p); - stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; - - fp = thread_saved_fp(p); - do { - if (fp < stack_start || fp > stack_end) - return 0; - lr = ((unsigned long *)fp)[0]; - if (!in_sched_functions(lr)) - return lr; - fp = *(unsigned long *)(fp + 4); - } while (count++ < 16); - } - return 0; -} --- a/arch/openrisc/include/asm/processor.h +++ b/arch/openrisc/include/asm/processor.h @@ -73,7 +73,6 @@ struct thread_struct { void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp); void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); #define cpu_relax() barrier() --- a/arch/openrisc/kernel/process.c +++ b/arch/openrisc/kernel/process.c @@ -263,9 +263,3 @@ void dump_elf_thread(elf_greg_t *dest, s dest[35] = 0; } -unsigned long __get_wchan(struct task_struct *p) -{ - /* TODO */ - - return 0; -} --- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -273,8 +273,6 @@ struct mm_struct; /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) ((tsk)->thread.regs.iaoq[0]) #define KSTK_ESP(tsk) ((tsk)->thread.regs.gr[30]) --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -239,30 +239,6 @@ copy_thread(unsigned long clone_flags, u return 0; } -unsigned long -__get_wchan(struct task_struct *p) -{ - struct unwind_frame_info info; - unsigned long ip; - int count = 0; - - /* - * These bracket the sleeping functions.. - */ - - unwind_frame_init_from_blocked_task(&info, p); - do { - if (unwind_once(&info) < 0) - return 0; - if (task_is_running(p)) - return 0; - ip = info.ip; - if (!in_sched_functions(ip)) - return ip; - } while (count++ < MAX_UNWIND_ENTRIES); - return 0; -} - #ifdef CONFIG_64BIT void *dereference_function_descriptor(void *ptr) { --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -300,8 +300,6 @@ struct thread_struct { #define task_pt_regs(tsk) ((tsk)->thread.regs) -unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->nip: 0) #define KSTK_ESP(tsk) ((tsk)->thread.regs? (tsk)->thread.regs->gpr[1]: 0) --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2111,43 +2111,6 @@ int validate_sp(unsigned long sp, struct EXPORT_SYMBOL(validate_sp); -static unsigned long ___get_wchan(struct task_struct *p) -{ - unsigned long ip, sp; - int count = 0; - - sp = p->thread.ksp; - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD)) - return 0; - - do { - sp = *(unsigned long *)sp; - if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) || - task_is_running(p)) - return 0; - if (count > 0) { - ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE]; - if (!in_sched_functions(ip)) - return ip; - } - } while (count++ < 16); - return 0; -} - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long ret; - - if (!try_get_task_stack(p)) - return 0; - - ret = ___get_wchan(p); - - put_task_stack(p); - - return ret; -} - static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; void __no_sanitize_address show_stack(struct task_struct *tsk, --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -66,9 +66,6 @@ static inline void release_thread(struct { } -extern unsigned long __get_wchan(struct task_struct *p); - - static inline void wait_for_interrupt(void) { __asm__ __volatile__ ("wfi"); --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -118,27 +118,6 @@ void show_stack(struct task_struct *task dump_backtrace(NULL, task, loglvl); } -static bool save_wchan(void *arg, unsigned long pc) -{ - if (!in_sched_functions(pc)) { - unsigned long *p = arg; - *p = pc; - return false; - } - return true; -} - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc = 0; - - if (!try_get_task_stack(task)) - return 0; - walk_stackframe(task, NULL, save_wchan, &pc); - put_task_stack(task); - return pc; -} - #ifdef CONFIG_STACKTRACE noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -192,7 +192,6 @@ static inline void release_thread(struct void guarded_storage_release(struct task_struct *tsk); void gs_load_bc_cb(struct pt_regs *regs); -unsigned long __get_wchan(struct task_struct *p); #define task_pt_regs(tsk) ((struct pt_regs *) \ (task_stack_page(tsk) + THREAD_SIZE) - 1) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->psw.addr) --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -181,35 +181,6 @@ void execve_tail(void) asm volatile("sfpc %0" : : "d" (0)); } -unsigned long __get_wchan(struct task_struct *p) -{ - struct unwind_state state; - unsigned long ip = 0; - - if (!task_stack_page(p)) - return 0; - - if (!try_get_task_stack(p)) - return 0; - - unwind_for_each_frame(&state, p, NULL, 0) { - if (state.stack_info.type != STACK_TYPE_TASK) { - ip = 0; - break; - } - - ip = unwind_get_return_address(&state); - if (!ip) - break; - - if (!in_sched_functions(ip)) - break; - } - - put_task_stack(p); - return ip; -} - unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) --- a/arch/sh/include/asm/processor_32.h +++ b/arch/sh/include/asm/processor_32.h @@ -180,8 +180,6 @@ static inline void show_code(struct pt_r } #endif -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[15]) --- a/arch/sh/kernel/process_32.c +++ b/arch/sh/kernel/process_32.c @@ -181,22 +181,3 @@ __switch_to(struct task_struct *prev, st return prev; } - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long pc; - - /* - * The same comment as on the Alpha applies here, too ... - */ - pc = thread_saved_pc(p); - -#ifdef CONFIG_FRAME_POINTER - if (in_sched_functions(pc)) { - unsigned long schedule_frame = (unsigned long)p->thread.sp; - return ((unsigned long *)schedule_frame)[21]; - } -#endif - - return pc; -} --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -183,8 +183,6 @@ do { \ /* Free all resources held by a thread. */ #define release_thread(tsk) do { } while (0) -unsigned long __get_wchan(struct task_struct *task); - #define task_pt_regs(tsk) (task_thread_info(tsk)->kregs) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->tpc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->u_regs[UREG_FP]) --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -662,31 +662,3 @@ int arch_dup_task_struct(struct task_str *dst = *src; return 0; } - -unsigned long __get_wchan(struct task_struct *task) -{ - unsigned long pc, fp, bias = 0; - struct thread_info *tp; - struct reg_window *rw; - unsigned long ret = 0; - int count = 0; - - tp = task_thread_info(task); - bias = STACK_BIAS; - fp = task_thread_info(task)->ksp + bias; - - do { - if (!kstack_valid(tp, fp)) - break; - rw = (struct reg_window *) fp; - pc = rw->ins[7]; - if (!in_sched_functions(pc)) { - ret = pc; - goto out; - } - fp = rw->ins[6] + bias; - } while (++count < 16); - -out: - return ret; -} --- a/arch/um/include/asm/processor-generic.h +++ b/arch/um/include/asm/processor-generic.h @@ -106,6 +106,5 @@ extern struct cpuinfo_um boot_cpu_data; #define cache_line_size() (boot_cpu_data.cache_alignment) #define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf) -extern unsigned long __get_wchan(struct task_struct *p); #endif --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -364,38 +364,6 @@ unsigned long arch_align_stack(unsigned } #endif -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long stack_page, sp, ip; - bool seen_sched = 0; - - stack_page = (unsigned long) task_stack_page(p); - /* Bail if the process has no kernel stack for some reason */ - if (stack_page == 0) - return 0; - - sp = p->thread.switch_buf->JB_SP; - /* - * Bail if the stack pointer is below the bottom of the kernel - * stack for some reason - */ - if (sp < stack_page) - return 0; - - while (sp < stack_page + THREAD_SIZE) { - ip = *((unsigned long *) sp); - if (in_sched_functions(ip)) - /* Ignore everything until we're above the scheduler */ - seen_sched = 1; - else if (kernel_text_address(ip) && seen_sched) - return ip; - - sp += sizeof(unsigned long); - } - - return 0; -} - int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu) { int cpu = current_thread_info()->cpu; --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -590,8 +590,6 @@ static inline void load_sp0(unsigned lon /* Free all resources held by a thread. */ extern void release_thread(struct task_struct *); -unsigned long __get_wchan(struct task_struct *p); - /* * Generic CPUID function * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -937,20 +937,6 @@ unsigned long arch_randomize_brk(struct return randomize_page(mm->brk, 0x02000000); } -/* - * Called from fs/proc with a reference on @p to find the function - * which called into schedule(). This needs to be done carefully - * because the task might wake up and we might look at a stack - * changing under us. - */ -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long entry = 0; - - stack_trace_save_tsk(p, &entry, 1, 0); - return entry; -} - long do_arch_prctl_common(struct task_struct *task, int option, unsigned long cpuid_enabled) { --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -215,8 +215,6 @@ struct mm_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) -extern unsigned long __get_wchan(struct task_struct *p); - #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1]) --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -293,32 +293,3 @@ int copy_thread(unsigned long clone_flag return 0; } - -/* - * These bracket the sleeping functions.. - */ - -unsigned long __get_wchan(struct task_struct *p) -{ - unsigned long sp, pc; - unsigned long stack_page = (unsigned long) task_stack_page(p); - int count = 0; - - sp = p->thread.sp; - pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp); - - do { - if (sp < stack_page + sizeof(struct task_struct) || - sp >= (stack_page + THREAD_SIZE) || - pc == 0) - return 0; - if (!in_sched_functions(pc)) - return pc; - - /* Stack layout: sp-4: ra, sp-3: sp' */ - - pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), sp); - sp = SPILL_SLOT(sp, 1); - } while (count++ < 16); - return 0; -} --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1966,6 +1966,21 @@ bool sched_task_on_rq(struct task_struct return task_on_rq_queued(p); } +#ifdef CONFIG_STACKTRACE +static unsigned long __get_wchan(struct task_struct *p) +{ + unsigned long entry = 0; + + stack_trace_save_tsk(p, &entry, 1, 0); + + return entry; +} +#endif + +/* + * Called from fs/proc with a reference on @p to find the function + * which called into schedule(). + */ unsigned long get_wchan(struct task_struct *p) { unsigned long ip = 0; --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1531,13 +1531,8 @@ config DEBUG_IRQFLAGS are enabled. config STACKTRACE - bool "Stack backtrace support" + def_bool y depends on STACKTRACE_SUPPORT - help - This option causes the kernel to create a /proc/pid/stack for - every process, showing its current stack trace. - It is also used by various kernel debugging features that require - stack trace generation. config WARN_ALL_UNSEEDED_RANDOM bool "Warn for all uses of unseeded randomness" From patchwork Fri Oct 8 11:15:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12545025 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B76BCC433EF for ; Fri, 8 Oct 2021 11:19:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FC6960F5B for ; 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Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYnsE-008eLN-3c; Fri, 08 Oct 2021 11:17:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C305E302D45; Fri, 8 Oct 2021 13:17:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id F0ABC2DB84A6C; Fri, 8 Oct 2021 13:17:07 +0200 (CEST) Message-ID: <20211008111626.455137084@infradead.org> User-Agent: quilt/0.66 Date: Fri, 08 Oct 2021 13:15:34 +0200 From: Peter Zijlstra To: keescook@chromium.org, jannh@google.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: [PATCH 7/7] arch: Fix STACKTRACE_SUPPORT References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org A few archs got save_stack_trace_tsk() vs in_sched_functions() wrong. Signed-off-by: Peter Zijlstra (Intel) --- arch/csky/kernel/stacktrace.c | 7 ++++++- arch/mips/kernel/stacktrace.c | 27 ++++++++++++++++----------- arch/nds32/kernel/stacktrace.c | 21 +++++++++++---------- 3 files changed, 33 insertions(+), 22 deletions(-) --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -122,12 +122,17 @@ static bool save_trace(unsigned long pc, return __save_trace(pc, arg, false); } +static bool save_trace_nosched(unsigned long pc, void *arg) +{ + return __save_trace(pc, arg, true); +} + /* * Save stack-backtrace addresses into a stack_trace buffer. */ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) { - walk_stackframe(tsk, NULL, save_trace, trace); + walk_stackframe(tsk, NULL, save_trace_nosched, trace); } EXPORT_SYMBOL_GPL(save_stack_trace_tsk); --- a/arch/mips/kernel/stacktrace.c +++ b/arch/mips/kernel/stacktrace.c @@ -66,16 +66,7 @@ static void save_context_stack(struct st #endif } -/* - * Save stack-backtrace addresses into a stack_trace buffer. - */ -void save_stack_trace(struct stack_trace *trace) -{ - save_stack_trace_tsk(current, trace); -} -EXPORT_SYMBOL_GPL(save_stack_trace); - -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +static void __save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace, bool savesched) { struct pt_regs dummyregs; struct pt_regs *regs = &dummyregs; @@ -88,6 +79,20 @@ void save_stack_trace_tsk(struct task_st regs->cp0_epc = tsk->thread.reg31; } else prepare_frametrace(regs); - save_context_stack(trace, tsk, regs, tsk == current); + save_context_stack(trace, tsk, regs, savesched); +} + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + */ +void save_stack_trace(struct stack_trace *trace) +{ + __save_stack_trace_tsk(current, trace, true); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + __save_stack_trace_tsk(tsk, trace, false); } EXPORT_SYMBOL_GPL(save_stack_trace_tsk); --- a/arch/nds32/kernel/stacktrace.c +++ b/arch/nds32/kernel/stacktrace.c @@ -6,25 +6,16 @@ #include #include -void save_stack_trace(struct stack_trace *trace) -{ - save_stack_trace_tsk(current, trace); -} -EXPORT_SYMBOL_GPL(save_stack_trace); - -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +static void __save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace, bool savesched) { unsigned long *fpn; int skip = trace->skip; - int savesched; int graph_idx = 0; if (tsk == current) { __asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(fpn)); - savesched = 1; } else { fpn = (unsigned long *)thread_saved_fp(tsk); - savesched = 0; } while (!kstack_end(fpn) && !((unsigned long)fpn & 0x3) @@ -50,4 +41,14 @@ void save_stack_trace_tsk(struct task_st fpn = (unsigned long *)fpp; } } +void save_stack_trace(struct stack_trace *trace) +{ + __save_stack_trace_tsk(current, trace, true); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + __save_stack_trace_tsk(tsk, trace, false); +} EXPORT_SYMBOL_GPL(save_stack_trace_tsk);