Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751027AbaDNGq4 (ORCPT ); Mon, 14 Apr 2014 02:46:56 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:41120 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750790AbaDNGqy (ORCPT ); Mon, 14 Apr 2014 02:46:54 -0400 X-IronPort-AV: E=Sophos;i="4.97,854,1389715200"; d="scan'208";a="29218138" Message-ID: <534B8540.4000904@cn.fujitsu.com> Date: Mon, 14 Apr 2014 14:50:40 +0800 From: Lai Jiangshan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Daeseok Youn CC: , Subject: Re: [PATCH] workqueue: fix double unlock bug References: <5462835.Vnc4dWZRns@daeseok-laptop.cloud.net> In-Reply-To: <5462835.Vnc4dWZRns@daeseok-laptop.cloud.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/14/2014 08:58 AM, Daeseok Youn wrote: > > mutex_unlock() and put_pwq_unlocked() do not need to be called > when alloc_unbound_pwq() is failed. > > Signed-off-by: Daeseok Youn > --- > kernel/workqueue.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 0ee63af..e6e9f6a 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4100,7 +4100,7 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu, > if (!pwq) { > pr_warning("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n", > wq->name); > - goto out_unlock; > + return; > } > > /* Nice catch!!! The supposed correct behavior is documented in the head of this function. We forgot to do it. * If NUMA affinity can't be adjusted due to memory allocation failure, it * falls back to @wq->dfl_pwq which may not be optimal but is always * correct. Could you use the following code instead of "goto out_unlock": mutex_lock(&wq->mutex); if (pwq == wq->dfl_pwq) goto out_unlock; else goto use_dfl_pwq; Correct&BAD. There are two blocks of suck code in this function: if (pwq == wq->dfl_pwq) goto out_unlock; else goto use_dfl_pwq; You can replace both these two blocks code to the following code: goto use_dfl_pwq; The result is the same as before except it adds some small overhead. I don't care the small overhead in this function. Thanks Lai -- 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/