From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755384AbbAFOK3 (ORCPT ); Tue, 6 Jan 2015 09:10:29 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:36162 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754014AbbAFOK2 (ORCPT ); Tue, 6 Jan 2015 09:10:28 -0500 Date: Tue, 6 Jan 2015 15:10:12 +0100 From: Peter Zijlstra To: Tetsuo Handa Cc: mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/fair: Fix RCU stall upon ENOMEM at sched_create_group(). Message-ID: <20150106141012.GY29390@twins.programming.kicks-ass.net> References: <201412252210.GCC30204.SOMVFFOtQJFLOH@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201412252210.GCC30204.SOMVFFOtQJFLOH@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 25, 2014 at 10:10:45PM +0900, Tetsuo Handa wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index ef2b104..586ee15 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7756,8 +7756,12 @@ static void task_move_group_fair(struct task_struct *p, int queued) > void free_fair_sched_group(struct task_group *tg) > { > int i; > + struct cfs_bandwidth *cfs_b; > > - destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); > + /* Check whether init_cfs_bandwidth() was called. */ > + cfs_b = tg_cfs_bandwidth(tg); > + if (cfs_b->throttled_cfs_rq.next) > + destroy_cfs_bandwidth(cfs_b); > > for_each_possible_cpu(i) { > if (tg->cfs_rq) This doesn't actually compile for !CONFIG_CFS_BANDWIDTH, how about: --- --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4005,6 +4005,10 @@ void __start_cfs_bandwidth(struct cfs_ba static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) { + /* init_cfs_bandwidth() was not called */ + if (!cfs_b->throttled_cfs_rq.next) + return; + hrtimer_cancel(&cfs_b->period_timer); hrtimer_cancel(&cfs_b->slack_timer); }