From: Tejun Heo <tj@kernel.org>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>, Phil Auld <pauld@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Lai Jiangshan <jiangshan.ljs@antgroup.com>,
Zqiang <qiang1.zhang@intel.com>
Subject: Re: [PATCH] workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex
Date: Fri, 26 Aug 2022 14:33:51 -1000 [thread overview]
Message-ID: <Ywlmb1ADhHnfFUI8@slm.duckdns.org> (raw)
In-Reply-To: <20220818143348.1134136-1-jiangshanlai@gmail.com>
Hello,
On Thu, Aug 18, 2022 at 10:33:48PM +0800, Lai Jiangshan wrote:
> @@ -5342,6 +5344,11 @@ static int workqueue_apply_unbound_cpumask(void)
> apply_wqattrs_cleanup(ctx);
> }
>
> + if (!ret) {
> + mutex_lock(&wq_pool_attach_mutex);
> + cpumask_copy(wq_unbound_cpumask, unbound_cpumask);
> + mutex_unlock(&wq_pool_attach_mutex);
Is this enough? Shouldn't the lock be protecting a wider scope? If there's
someone reading the flag with just pool_attach_mutex, what prevents them
reading it right before the new value is committed and keeps using the stale
value?
Thanks.
--
tejun
next prev parent reply other threads:[~2022-08-27 0:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 8:41 [RFC PATCH v3 0/3] workqueue: destroy_worker() vs isolated CPUs Valentin Schneider
2022-08-02 8:41 ` [RFC PATCH v3 1/3] workqueue: Hold wq_pool_mutex while affining tasks to wq_unbound_cpumask Valentin Schneider
2022-08-03 3:40 ` Lai Jiangshan
2022-08-04 11:40 ` Valentin Schneider
2022-08-05 2:43 ` Lai Jiangshan
2022-08-15 23:50 ` Tejun Heo
2022-08-18 14:33 ` [PATCH] workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex Lai Jiangshan
2022-08-27 0:33 ` Tejun Heo [this message]
2022-08-30 9:32 ` Lai Jiangshan
2022-09-04 20:23 ` Tejun Heo
2022-08-30 14:16 ` [RFC PATCH v3 1/3] workqueue: Hold wq_pool_mutex while affining tasks to wq_unbound_cpumask Lai Jiangshan
2022-08-02 8:41 ` [RFC PATCH v3 2/3] workqueue: Unbind workers before sending them to exit() Valentin Schneider
2022-08-05 3:16 ` Lai Jiangshan
2022-08-05 16:47 ` Valentin Schneider
2022-08-02 8:41 ` [RFC PATCH v3 3/3] DEBUG-DO-NOT-MERGE: workqueue: kworker spawner Valentin Schneider
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