From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932813AbcFCUKi (ORCPT ); Fri, 3 Jun 2016 16:10:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50542 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932538AbcFCUK3 (ORCPT ); Fri, 3 Jun 2016 16:10:29 -0400 From: Daniel Bristot de Oliveira To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Christian Borntraeger , "Luis Claudio R. Goncalves" Subject: [PATCH] sched: Panic on scheduling while atomic if kernel.panic_on_warn is set Date: Fri, 3 Jun 2016 17:10:18 -0300 Message-Id: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 03 Jun 2016 20:10:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, a schedule while atomic error prints the stack trace to the kernel log and the system continue running. Although it is possible to collect the kernel log messages and analyze it, often more information are needed. Furthermore, keep the system running is not always the best choice. For example, when the preempt count underflows the system will not stop to complain about scheduling while atomic, so the kernel log can wrap around overwriting the first stack trace, tuning the analysis even more challenging. This patch uses the kernel.panic_on_warn sysctl to help out on these more complex situations. When kernel.panic_on_warn is set to 1, the kernel will panic() in the schedule while atomic detection. The default value of the sysctl is 0, maintaining the current behavior. Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Christian Borntraeger Cc: "Luis Claudio R. Goncalves" Signed-off-by: Daniel Bristot de Oliveira --- kernel/sched/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7f2cae4..7d07ed9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3146,6 +3146,9 @@ static noinline void __schedule_bug(struct task_struct *prev) pr_cont("\n"); } #endif + if (panic_on_warn) + panic("scheduling while atomic\n"); + dump_stack(); add_taint(TAINT_WARN, LOCKDEP_STILL_OK); } -- 2.5.5