From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1955459AbdDZIcF (ORCPT ); Wed, 26 Apr 2017 04:32:05 -0400 Received: from terminus.zytor.com ([65.50.211.136]:46945 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1949328AbdDZIbv (ORCPT ); Wed, 26 Apr 2017 04:31:51 -0400 Date: Wed, 26 Apr 2017 01:25:26 -0700 From: tip-bot for Josh Poimboeuf Message-ID: Cc: tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, torvalds@linux-foundation.org, jpoimboe@redhat.com, luto@kernel.org, brgerst@gmail.com, dvlasenk@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org Reply-To: mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, bp@alien8.de, luto@kernel.org, brgerst@gmail.com, jpoimboe@redhat.com, dvlasenk@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com In-Reply-To: <016d6a9810d7d1bfc87ef8c0e6ee041c6744c909.1493171120.git.jpoimboe@redhat.com> References: <016d6a9810d7d1bfc87ef8c0e6ee041c6744c909.1493171120.git.jpoimboe@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/unwind: Dump all stacks in unwind_dump() Git-Commit-ID: 262fa734a0023a43391f9bd4a4099487b8393f35 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 262fa734a0023a43391f9bd4a4099487b8393f35 Gitweb: http://git.kernel.org/tip/262fa734a0023a43391f9bd4a4099487b8393f35 Author: Josh Poimboeuf AuthorDate: Tue, 25 Apr 2017 20:48:52 -0500 Committer: Ingo Molnar CommitDate: Wed, 26 Apr 2017 08:19:05 +0200 x86/unwind: Dump all stacks in unwind_dump() Currently unwind_dump() dumps only the most recently accessed stack. But it has a few issues. In some cases, 'first_sp' can get out of sync with 'stack_info', causing unwind_dump() to start from the wrong address, flood the printk buffer, and eventually read a bad address. In other cases, dumping only the most recently accessed stack doesn't give enough data to diagnose the error. Fix both issues by dumping *all* stacks involved in the trace, not just the last one. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 8b5e99f02264 ("x86/unwind: Dump stack data on warnings") Link: http://lkml.kernel.org/r/016d6a9810d7d1bfc87ef8c0e6ee041c6744c909.1493171120.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/unwind_frame.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index ae0821f..fec70fe 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -30,6 +30,8 @@ static void unwind_dump(struct unwind_state *state) static bool dumped_before = false; bool prev_zero, zero = false; unsigned long word, *sp; + struct stack_info stack_info = {0}; + unsigned long visit_mask = 0; if (dumped_before) return; @@ -40,21 +42,27 @@ static void unwind_dump(struct unwind_state *state) state->stack_info.type, state->stack_info.next_sp, state->stack_mask, state->graph_idx); - for (sp = state->orig_sp; sp < state->stack_info.end; sp++) { - word = READ_ONCE_NOCHECK(*sp); + for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { + if (get_stack_info(sp, state->task, &stack_info, &visit_mask)) + break; - prev_zero = zero; - zero = word == 0; + for (; sp < stack_info.end; sp++) { - if (zero) { - if (!prev_zero) - printk_deferred("%p: %0*x ...\n", - sp, BITS_PER_LONG/4, 0); - continue; - } + word = READ_ONCE_NOCHECK(*sp); + + prev_zero = zero; + zero = word == 0; - printk_deferred("%p: %0*lx (%pB)\n", - sp, BITS_PER_LONG/4, word, (void *)word); + if (zero) { + if (!prev_zero) + printk_deferred("%p: %0*x ...\n", + sp, BITS_PER_LONG/4, 0); + continue; + } + + printk_deferred("%p: %0*lx (%pB)\n", + sp, BITS_PER_LONG/4, word, (void *)word); + } } } @@ -216,7 +224,7 @@ static bool update_stack_state(struct unwind_state *state, } /* Save the original stack pointer for unwind_dump(): */ - if (!state->orig_sp || info->type != prev_type) + if (!state->orig_sp) state->orig_sp = frame; return true;