From: Bart Van Assche <bvanassche@acm.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
syzbot <syzbot+831661966588c802aae9@syzkaller.appspotmail.com>,
jgg@ziepe.ca, linux-kernel@vger.kernel.org,
linux-rdma@vger.kernel.org, syzkaller-bugs@googlegroups.com,
Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>
Subject: Re: [syzbot] possible deadlock in worker_thread
Date: Sat, 12 Feb 2022 08:37:55 -0800 [thread overview]
Message-ID: <71d6f14e-46af-cc5a-bc70-af1cdc6de8d5@acm.org> (raw)
In-Reply-To: <ccd04d8a-154b-543e-e1c3-84bc655508d1@I-love.SAKURA.ne.jp>
On 2/11/22 21:31, Tetsuo Handa wrote:
> But this report might be suggesting us that we should consider
> deprecating (and eventually getting rid of) system-wide workqueues
> (declared in include/linux/workqueue.h), for since flush_workqueue()
> synchronously waits for completion, sharing system-wide workqueues
> among multiple modules can generate unexpected locking dependency
> chain (like this report).
I do not agree with deprecating system-wide workqueues. I think that all
flush_workqueue(system_long_wq) calls should be reviewed since these are
deadlock-prone.
Thanks,
Bart.
next prev parent reply other threads:[~2022-02-12 16:38 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 19:27 [syzbot] possible deadlock in worker_thread syzbot
2022-02-11 18:59 ` Bart Van Assche
2022-02-12 5:31 ` Tetsuo Handa
2022-02-12 16:37 ` Bart Van Assche [this message]
2022-02-12 17:14 ` Tetsuo Handa
2022-02-13 15:33 ` Leon Romanovsky
2022-02-13 23:06 ` Bart Van Assche
2022-02-14 1:08 ` Tetsuo Handa
2022-02-14 3:44 ` Tejun Heo
2022-02-14 13:36 ` Tetsuo Handa
2022-02-14 17:34 ` Tejun Heo
2022-02-15 10:26 ` Tetsuo Handa
2022-02-15 10:43 ` Haakon Bugge
2022-02-15 12:48 ` Tetsuo Handa
2022-02-15 17:05 ` Bart Van Assche
2022-02-15 22:05 ` Tetsuo Handa
2022-02-22 18:26 ` Tejun Heo
2022-02-17 11:22 ` [PATCH v2] workqueue: Warn flush attempt using system-wide workqueues Tetsuo Handa
2022-02-22 18:36 ` Tejun Heo
[not found] ` <CGME20220223212048eucas1p1fab5e35ff398eff57808a8f1125dd15f@eucas1p1.samsung.com>
2022-02-23 21:20 ` Marek Szyprowski
2022-02-23 21:35 ` Tejun Heo
2022-02-23 22:06 ` Tetsuo Handa
2022-02-17 12:27 ` [syzbot] possible deadlock in worker_thread Fabio M. De Francesco
2022-02-22 18:30 ` Tejun Heo
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