linux-kernel - Re: [PATCH v2] workqueue: Fix UAF report by KASAN in pwq_release

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Message-ID: <ZQndj34e9lOpA8Fm@slm.duckdns.org>
Date:   Tue, 19 Sep 2023 07:42:39 -1000
From:   Tejun Heo <tj@...nel.org>
To:     Zqiang <qiang.zhang1211@...il.com>
Cc:     jiangshanlai@...il.com, syzkaller-bugs@...glegroups.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] workqueue: Fix UAF report by KASAN in
 pwq_release_workfn()

Hello,

The patch looks fine but

On Tue, Sep 19, 2023 at 04:19:58PM +0800, Zqiang wrote:
> @@ -4743,6 +4743,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
>  	wq_free_lockdep(wq);
>  err_free_wq:
>  	free_workqueue_attrs(wq->unbound_attrs);

Can you please add a comment here explaining why the flushing is necessary?

> +	if (wq->flags & WQ_UNBOUND)
> +		kthread_flush_worker(pwq_release_worker);

Thanks.

-- 
tejun