From: Jens Axboe <[email protected]>
To: Hao Xu <[email protected]>
Cc: [email protected], Pavel Begunkov <[email protected]>,
Joseph Qi <[email protected]>
Subject: Re: [PATCH 4/4] io-wq: fix potential race of acct->nr_workers
Date: Sun, 12 Sep 2021 12:23:31 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 9/11/21 1:40 PM, Hao Xu wrote:
> Given max_worker is 1, and we currently have 1 running and it is
> exiting. There may be race like:
> io_wqe_enqueue worker1
> no work there and timeout
> unlock(wqe->lock)
> ->insert work
> -->io_worker_exit
> lock(wqe->lock)
> ->if(!nr_workers) //it's still 1
> unlock(wqe->lock)
> goto run_cancel
> lock(wqe->lock)
> nr_workers--
> ->dec_running
> ->worker creation fails
> unlock(wqe->lock)
>
> We enqueued one work but there is no workers, causes hung.
This one also looks good, applied.
--
Jens Axboe
prev parent reply other threads:[~2021-09-12 18:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 19:40 [PATCH 0/4] iowq fix Hao Xu
2021-09-11 19:40 ` [PATCH 1/4] io-wq: tweak return value of io_wqe_create_worker() Hao Xu
2021-09-12 18:10 ` Jens Axboe
2021-09-12 19:02 ` Hao Xu
2021-09-12 21:34 ` Jens Axboe
2021-09-13 6:37 ` Hao Xu
2021-09-11 19:40 ` [PATCH 2/4] io-wq: code clean " Hao Xu
2021-09-12 18:18 ` Jens Axboe
2021-09-13 8:30 ` Hao Xu
2021-09-11 19:40 ` [PATCH 3/4] io-wq: fix worker->refcount when creating worker in work exit Hao Xu
2021-09-11 22:13 ` Jens Axboe
2021-09-12 9:04 ` Hao Xu
2021-09-12 18:07 ` Jens Axboe
2021-09-11 19:40 ` [PATCH 4/4] io-wq: fix potential race of acct->nr_workers Hao Xu
2021-09-12 18:23 ` Jens Axboe [this message]
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