From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161420AbaDPXam (ORCPT ); Wed, 16 Apr 2014 19:30:42 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:15625 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753294AbaDPXak (ORCPT ); Wed, 16 Apr 2014 19:30:40 -0400 X-IronPort-AV: E=Sophos;i="4.97,875,1389715200"; d="scan'208";a="29364837" From: Lai Jiangshan To: Tejun Heo , CC: Lai Jiangshan Subject: [PATCH 1/2] workqueue: rescuer_thread() processes all pwqs before exit Date: Thu, 17 Apr 2014 07:34:08 +0800 Message-ID: <1397691258-11639-1-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <20140416165052.GK1257@htj.dyndns.org> References: <20140416165052.GK1257@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Before the rescuer is picked to running, the works of the @pwq may be processed by some other workers, and destroy_workqueue() may called at the same time. This may result a nasty situation that rescuer may exit with non-empty mayday list. It is no harm currently, destroy_workqueue() can safely to free them all(workqueue&pwqs) togerther, since the rescuer is stopped. No rescuer nor mayday-timer can access the mayday list. But it is nasty and error-prone in future develop. Fix it. Signed-off-by: Lai Jiangshan --- kernel/workqueue.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 0ee63af..832125f 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2409,12 +2409,6 @@ static int rescuer_thread(void *__rescuer) repeat: set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_stop()) { - __set_current_state(TASK_RUNNING); - rescuer->task->flags &= ~PF_WQ_WORKER; - return 0; - } - /* see whether any pwq is asking for help */ spin_lock_irq(&wq_mayday_lock); @@ -2459,6 +2453,12 @@ repeat: spin_unlock_irq(&wq_mayday_lock); + if (kthread_should_stop()) { + __set_current_state(TASK_RUNNING); + rescuer->task->flags &= ~PF_WQ_WORKER; + return 0; + } + /* rescuers should never participate in concurrency management */ WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); schedule(); -- 1.7.4.4