From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755036Ab2CXH5I (ORCPT ); Sat, 24 Mar 2012 03:57:08 -0400 Received: from terminus.zytor.com ([198.137.202.10]:60539 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752687Ab2CXH5F (ORCPT ); Sat, 24 Mar 2012 03:57:05 -0400 Date: Sat, 24 Mar 2012 00:56:53 -0700 From: tip-bot for Hugh Dickins Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, hughd@google.com, namhyung@gmail.com, fweisbec@gmail.com, akpm@linux-foundation.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, hughd@google.com, namhyung@gmail.com, fweisbec@gmail.com, akpm@linux-foundation.org, tglx@linutronix.de In-Reply-To: <20120323225648.15DD5A033B@akpm.mtv.corp.google.com> References: <20120323225648.15DD5A033B@akpm.mtv.corp.google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86: Stop recursive fault in print_context_stack after stack overflow Git-Commit-ID: 65c0ff4079c011232e795e62c74a0a95512b7ac3 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 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Sat, 24 Mar 2012 00:56:58 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 65c0ff4079c011232e795e62c74a0a95512b7ac3 Gitweb: http://git.kernel.org/tip/65c0ff4079c011232e795e62c74a0a95512b7ac3 Author: Hugh Dickins AuthorDate: Fri, 23 Mar 2012 14:02:55 -0700 Committer: Ingo Molnar CommitDate: Sat, 24 Mar 2012 08:15:04 +0100 x86: Stop recursive fault in print_context_stack after stack overflow After printing out the first line of a stack backtrace, print_context_stack() calls print_ftrace_graph_addr() to check if it's making a graph of function calls, usually not the case. But unfortunate ordering of assignments causes this to oops if an earlier stack overflow corrupted threadinfo->task. Reorder to avoid that irritation. ( The fact that there was a stack overflow may often be more interesting than the stack that can now be shown; but integrating that information with this stacktrace is awkward, so leave it to overflow reporting. ) Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Cc: Namhyung Kim Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/20120323225648.15DD5A033B@akpm.mtv.corp.google.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 4025fe4..90bf130 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -37,13 +37,16 @@ print_ftrace_graph_addr(unsigned long addr, void *data, const struct stacktrace_ops *ops, struct thread_info *tinfo, int *graph) { - struct task_struct *task = tinfo->task; + struct task_struct *task; unsigned long ret_addr; - int index = task->curr_ret_stack; + int index; if (addr != (unsigned long)return_to_handler) return; + task = tinfo->task; + index = task->curr_ret_stack; + if (!task->ret_stack || index < *graph) return;