From patchwork Mon Apr 22 12:38:37 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 238512 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id B0AD52C0160 for ; Mon, 22 Apr 2013 22:38:48 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UUG14-00011g-84; Mon, 22 Apr 2013 12:38:42 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UUG11-0000zA-PX for kernel-team@lists.ubuntu.com; Mon, 22 Apr 2013 12:38:39 +0000 Received: from bl20-133-161.dsl.telepac.pt ([2.81.133.161] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UUG10-0003PN-Gk; Mon, 22 Apr 2013 12:38:38 +0000 From: Luis Henriques To: Tejun Heo Subject: [ 3.5.y.z extended stable ] Patch "sched: Convert BUG_ON()s in try_to_wake_up_local() to" has been added to staging queue Date: Mon, 22 Apr 2013 13:38:37 +0100 Message-Id: <1366634317-16980-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 X-Extended-Stable: 3.5 Cc: Peter Zijlstra , kernel-team@lists.ubuntu.com, Ingo Molnar , Steven Rostedt X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled sched: Convert BUG_ON()s in try_to_wake_up_local() to to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 35019587c05736a2c1a0484af215e7a05810d5de Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 18 Mar 2013 12:22:34 -0700 Subject: [PATCH] sched: Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s commit 383efcd00053ec40023010ce5034bd702e7ab373 upstream. 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 Acked-by: Steven Rostedt Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20130318192234.GD3042@htj.dyndns.org Signed-off-by: Ingo Molnar Signed-off-by: Luis Henriques --- kernel/sched/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) -- 1.8.1.2 diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3231df8..473cac3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1651,8 +1651,10 @@ 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)) {