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Date:   Thu, 15 Oct 2020 14:38:15 +0200
From:   Petr Mladek <pmladek@suse.com>
To:     akpm@linux-foundation.org
Cc:     tj@kernel.org, hdanton@sina.com,
        Zqiang <qiang.zhang@windriver.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH v4] kthread_worker: Prevent queuing delayed work from
 timer_fn when it is being canceled
Message-ID: <20201015123815.GE8871@alley>
References: <20201014075048.15473-1-qiang.zhang@windriver.com>
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In-Reply-To: <20201014075048.15473-1-qiang.zhang@windriver.com>
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On Wed 2020-10-14 15:50:48, Zqiang wrote:
> There is a small race window when a delayed work is being canceled and
> the work still might be queued from the timer_fn:
> 
> 	CPU0						CPU1
> kthread_cancel_delayed_work_sync()
>    __kthread_cancel_work_sync()
>      __kthread_cancel_work()
>         work->canceling++;
> 					      kthread_delayed_work_timer_fn()
> 						   kthread_insert_work();
> 
> BUG: kthread_insert_work() should not get called when work->canceling
> is set.
> 
> Cc: <stable@vger.kernel.org>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> Acked-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Zqiang <qiang.zhang@windriver.com>

Andrew, are you going to take this patch with -mm tree, please?

I think that you usually take the changes in kthread.c.

Best Regards,
Petr