From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754897Ab3CRTWj (ORCPT ); Mon, 18 Mar 2013 15:22:39 -0400 Received: from mail-da0-f50.google.com ([209.85.210.50]:42428 "EHLO mail-da0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752355Ab3CRTWi (ORCPT ); Mon, 18 Mar 2013 15:22:38 -0400 Date: Mon, 18 Mar 2013 12:22:34 -0700 From: Tejun Heo To: Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Steven Rostedt Subject: [PATCH] scheduler: convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s Message-ID: <20130318192234.GD3042@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org try_to_wake_up_local() should only be invoked to wake up another task in the same runqueue and BUG_ON()s are used to enforce the rule. Missing try_to_wake_up_local() can stall workqueue execution but such stalls are likely to be finite either by another work item being queued or the one blocked getting unblocked. There's no reason to trigger BUG while holding rq lock crashing the whole system. Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s. Signed-off-by: Tejun Heo Cc: Steven Rostedt --- kernel/sched/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7f12624..a2eda4d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1498,8 +1498,10 @@ static void try_to_wake_up_local(struct task_struct *p) { struct rq *rq = task_rq(p); - BUG_ON(rq != this_rq()); - BUG_ON(p == current); + if (WARN_ON_ONCE(rq != this_rq()) || + WARN_ON_ONCE(p == current)) + return; + lockdep_assert_held(&rq->lock); if (!raw_spin_trylock(&p->pi_lock)) {