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Wed, 03 Jul 2024 11:14:47 -0400 X-MC-Unique: OJYKiDLNPneTrgKnO966pw-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B832619560A2; Wed, 3 Jul 2024 15:14:46 +0000 (UTC) Received: from [10.22.33.252] (unknown [10.22.33.252]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8743C1955F21; Wed, 3 Jul 2024 15:14:45 +0000 (UTC) Message-ID: <7b105f07-5c13-4f69-9834-05e7054ddb36@redhat.com> Date: Wed, 3 Jul 2024 11:14:44 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/6] workqueue: Protect wq_unbound_cpumask with wq_pool_attach_mutex in init_rescuer() To: Lai Jiangshan , linux-kernel@vger.kernel.org Cc: Lai Jiangshan , Tejun Heo References: <20240703033855.3373-1-jiangshanlai@gmail.com> <20240703033855.3373-3-jiangshanlai@gmail.com> Content-Language: en-US From: Waiman Long In-Reply-To: <20240703033855.3373-3-jiangshanlai@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On 7/2/24 23:38, Lai Jiangshan wrote: > From: Lai Jiangshan > > wq_unbound_cpumask can be possibly changed without wq_pool_attach_mutex > or wq_pool_mutex held in init_rescuer(). > > Use wq_pool_attach_mutex to protect it. > > Fixes: 49584bb8ddbe("workqueue: Bind unbound workqueue rescuer to wq_unbound_cpumask") > Signed-off-by: Lai Jiangshan > --- > kernel/workqueue.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index c738b3024cc2..cf1a129eb547 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -5533,6 +5533,9 @@ static int init_rescuer(struct workqueue_struct *wq) > return ret; > } > > + /* lock wq_pool_attach_mutex for wq_unbound_cpumask */ > + mutex_lock(&wq_pool_attach_mutex); > + > wq->rescuer = rescuer; > if (wq->flags & WQ_UNBOUND) > kthread_bind_mask(rescuer->task, wq_unbound_cpumask); > @@ -5540,6 +5543,8 @@ static int init_rescuer(struct workqueue_struct *wq) > kthread_bind_mask(rescuer->task, cpu_possible_mask); > wake_up_process(rescuer->task); > > + mutex_unlock(&wq_pool_attach_mutex); > + > return 0; > } > Reviewed-by: Waiman Long Thanks!