From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938562AbcKQHWF (ORCPT ); Thu, 17 Nov 2016 02:22:05 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39882 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932333AbcKQHWD (ORCPT ); Thu, 17 Nov 2016 02:22:03 -0500 Date: Wed, 16 Nov 2016 23:19:41 -0800 From: tip-bot for Josh Poimboeuf Message-ID: Cc: torvalds@linux-foundation.org, jpoimboe@redhat.com, mingo@kernel.org, peterz@infradead.org, bp@alien8.de, luto@kernel.org, dvlasenk@redhat.com, tglx@linutronix.de, brgerst@gmail.com, linux-kernel@vger.kernel.org, hpa@zytor.com Reply-To: peterz@infradead.org, jpoimboe@redhat.com, mingo@kernel.org, torvalds@linux-foundation.org, dvlasenk@redhat.com, luto@kernel.org, bp@alien8.de, tglx@linutronix.de, hpa@zytor.com, brgerst@gmail.com, linux-kernel@vger.kernel.org In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl() Git-Commit-ID: f4474c9f0bba17857b1a47c8dc89c07a0845c2b2 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: f4474c9f0bba17857b1a47c8dc89c07a0845c2b2 Gitweb: http://git.kernel.org/tip/f4474c9f0bba17857b1a47c8dc89c07a0845c2b2 Author: Josh Poimboeuf AuthorDate: Thu, 17 Nov 2016 00:04:58 -0600 Committer: Ingo Molnar CommitDate: Thu, 17 Nov 2016 07:48:39 +0100 x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl() When show_trace_log_lvl() is called from show_regs(), it completely fails to dump the stack. This bug was introduced when show_stack_log_lvl() was removed with the following commit: 0ee1dd9f5e7e ("x86/dumpstack: Remove raw stack dump") Previous callers of that function now call show_trace_log_lvl() directly. That resulted in a subtle change, in that the 'stack' argument can now be NULL in certain cases. A NULL 'stack' pointer means that the stack dump should start from the topmost stack frame unless 'regs' is valid, in which case it should start from 'regs->sp'. 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: 0ee1dd9f5e7e ("x86/dumpstack: Remove raw stack dump") Link: http://lkml.kernel.org/r/c551842302a9c222d96a14e42e4003f059509f69.1479362652.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 499aa6f..1e057b0 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -59,6 +59,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, printk("%sCall Trace:\n", log_lvl); unwind_start(&state, task, regs, stack); + stack = stack ? : get_stack_pointer(task, regs); /* * Iterate through the stacks, starting with the current stack pointer.