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From: Pavel Begunkov <asml.silence@gmail.com>
To: Hao Xu <haoxu@linux.alibaba.com>, Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org, Joseph Qi <joseph.qi@linux.alibaba.com>
Subject: Re: [PATCH 2/2] io_uring: don't hold uring_lock when calling io_run_task_work*
Date: Sun, 7 Feb 2021 17:16:34 +0000	[thread overview]
Message-ID: <433825b4-8330-b448-eeeb-4582c5b25159@gmail.com> (raw)
In-Reply-To: <62fc0e30-47bd-71d2-29e3-c2824bf78725@linux.alibaba.com>

On 06/02/2021 11:34, Hao Xu wrote:
> I saw percpu_ref_is_dying(&ctx->refs) check in sq thread but not
> in io_uring_enter(), so I guess there could be another thread doing
> io_uring_enter() and submiting sqes.

Ok, looks tryget does it in a different fashion than I recalled.

> So we can just put unlock and lock around io_run_task_work_sig()
> to address the issue 2?

io_set_resource_node()
	-> percpu_ref_get()

If refs are left dying, it won't be safe for in-parallel enters.
tryget or resurrect

-- 
Pavel Begunkov

  reply	other threads:[~2021-02-07 17:21 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03 14:57 [PATCH 0/2] fix deadlock in __io_req_task_submit() Hao Xu
2021-02-03 14:57 ` [PATCH 1/2] io_uring: add uring_lock as an argument to io_sqe_files_unregister() Hao Xu
2021-02-03 16:33   ` Pavel Begunkov
2021-02-04  3:34     ` Hao Xu
2021-02-04 11:11       ` Pavel Begunkov
2021-02-04 14:49         ` Jens Axboe
2021-02-03 14:57 ` [PATCH 2/2] io_uring: don't hold uring_lock when calling io_run_task_work* Hao Xu
2021-02-03 16:35   ` Pavel Begunkov
2021-02-03 16:45     ` Pavel Begunkov
2021-02-04  3:25       ` Hao Xu
2021-02-04 11:17         ` Pavel Begunkov
2021-02-04 15:26           ` Pavel Begunkov
2021-02-05  9:57             ` Hao Xu
2021-02-05 10:18               ` Pavel Begunkov
2021-02-06 11:34                 ` Hao Xu
2021-02-07 17:16                   ` Pavel Begunkov [this message]
2021-02-06 16:21                 ` Hao Xu
2021-02-11 13:30                 ` Hao Xu
2021-02-05 10:03       ` Hao Xu
2021-02-04 11:33   ` Pavel Begunkov

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