Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753915AbZKPRRg (ORCPT ); Mon, 16 Nov 2009 12:17:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753658AbZKPRRe (ORCPT ); Mon, 16 Nov 2009 12:17:34 -0500 Received: from hera.kernel.org ([140.211.167.34]:33315 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753683AbZKPRRd (ORCPT ); Mon, 16 Nov 2009 12:17:33 -0500 From: Tejun Heo To: linux-kernel@vger.kernel.org, jeff@garzik.org, mingo@elte.hu, akpm@linux-foundation.org, jens.axboe@oracle.com, rusty@rustcorp.com.au, cl@linux-foundation.org, dhowells@redhat.com, arjan@linux.intel.com, torvalds@linux-foundation.org, avi@redhat.com, peterz@infradead.org, andi@firstfloor.org, fweisbec@gmail.com Cc: Tejun Heo Subject: [PATCH 02/21] sched, kvm: fix race condition involving sched_in_preempt_notifers Date: Tue, 17 Nov 2009 02:15:07 +0900 Message-Id: <1258391726-30264-3-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.6.4.2 In-Reply-To: <1258391726-30264-1-git-send-email-tj@kernel.org> References: <1258391726-30264-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 36 In finish_task_switch(), fire_sched_in_preempt_notifiers() is called after finish_lock_switch(). However, depending on architecture, preemption can be enabled after finish_lock_switch() which breaks the semantics of preempt notifiers. Move it before finish_arch_switch(). This also makes in notifiers symmetric to out notifiers in terms of locking - now both are called under rq lock. Signed-off-by: Tejun Heo Cc: Avi Kivity --- kernel/sched.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 3c11ae0..de8a765 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2751,9 +2751,9 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) prev_state = prev->state; finish_arch_switch(prev); perf_event_task_sched_in(current, cpu_of(rq)); + fire_sched_in_preempt_notifiers(current); finish_lock_switch(rq, prev); - fire_sched_in_preempt_notifiers(current); if (mm) mmdrop(mm); if (unlikely(prev_state == TASK_DEAD)) { -- 1.6.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/