From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751770Ab1AQP77 (ORCPT ); Mon, 17 Jan 2011 10:59:59 -0500 Received: from casper.infradead.org ([85.118.1.10]:52409 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750990Ab1AQP76 convert rfc822-to-8bit (ORCPT ); Mon, 17 Jan 2011 10:59:58 -0500 Subject: Re: Bug in scheduler when using rt_mutex From: Peter Zijlstra To: samu.p.onkalo@nokia.com Cc: mingo@elte.hu, "linux-kernel@vger.kernel.org" , tglx In-Reply-To: <1295275365.12840.13.camel@kolo> References: <1295275365.12840.13.camel@kolo> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Mon, 17 Jan 2011 17:00:32 +0100 Message-ID: <1295280032.30950.128.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-01-17 at 16:42 +0200, Onkalo Samu wrote: > > Failure case: > - user process locks rt_mutex > - and goes to sleep (wait_for_completion etc.) > - user process is dequeued to sleep state > -> vruntime is not updated in dequeue_entity > Does the below (completely untested) patch help? --- kernel/sched.c | 6 +++++- kernel/sched_fair.c | 11 +++++++++++ 2 files changed, 16 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index a0eb094..be09581 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8108,8 +8108,10 @@ EXPORT_SYMBOL(__might_sleep); #ifdef CONFIG_MAGIC_SYSRQ static void normalize_task(struct rq *rq, struct task_struct *p) { + struct sched_class *prev_class = p->sched_class; + int old_prio = p->prio; int on_rq; - + on_rq = p->se.on_rq; if (on_rq) deactivate_task(rq, p, 0); @@ -8118,6 +8120,8 @@ static void normalize_task(struct rq *rq, struct task_struct *p) activate_task(rq, p, 0); resched_task(rq->curr); } + + check_class_changed(rq, p, prev_class, old_prio, task_current(rq, p)); } void normalize_rt_tasks(void) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index c62ebae..0a27b00 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -4072,6 +4072,17 @@ static void prio_changed_fair(struct rq *rq, struct task_struct *p, static void switched_to_fair(struct rq *rq, struct task_struct *p, int running) { + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + if (se->on_rq && cfs_rq->curr != se) + __dequeue_entity(cfs_rq, se); + + place_entity(cfs_rq, se, 0); + + if (se->on_rq && cfs_rq->curr != se) + __enqueue_entity(cfs_rq, se); + /* * We were most likely switched from sched_rt, so * kick off the schedule if running, otherwise just see