From: Pavel Begunkov <asml.silence@gmail.com>
To: Olivier Langlois <olivier@trillion01.com>,
Jens Axboe <axboe@kernel.dk>,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] io_uring: Fix race condition when sqp thread goes to sleep
Date: Wed, 23 Jun 2021 23:02:22 +0100 [thread overview]
Message-ID: <876d12ba-b71c-ba49-342e-6ad59b8dea15@gmail.com> (raw)
In-Reply-To: <d1419dc32ec6a97b453bee34dc03fa6a02797142.1624473200.git.olivier@trillion01.com>
On 6/23/21 7:50 PM, Olivier Langlois wrote:
> If an asynchronous completion happens before the task is preparing
> itself to wait and set its state to TASK_INTERRUPTIBLE, the completion
> will not wake up the sqp thread.
Looks good, the bug should be pretty old.
Cc: stable@vger.kernel.org
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
> Signed-off-by: Olivier Langlois <olivier@trillion01.com>
> ---
> fs/io_uring.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index fc8637f591a6..7c545fa66f31 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -6902,7 +6902,7 @@ static int io_sq_thread(void *data)
> }
>
> prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
> - if (!io_sqd_events_pending(sqd)) {
> + if (!io_sqd_events_pending(sqd) && !io_run_task_work()) {
> needs_sched = true;
> list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
> io_ring_set_wakeup_flag(ctx);
>
--
Pavel Begunkov
next prev parent reply other threads:[~2021-06-23 22:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 18:50 [PATCH v2 0/2] Minor SQPOLL thread fix and improvement Olivier Langlois
2021-06-23 18:50 ` [PATCH v2 1/2] io_uring: Fix race condition when sqp thread goes to sleep Olivier Langlois
2021-06-23 22:02 ` Pavel Begunkov [this message]
2021-06-23 18:50 ` [PATCH v2 2/2] io_uring: Create define to modify a SQPOLL parameter Olivier Langlois
2021-06-23 22:14 ` Pavel Begunkov
2021-06-23 22:24 ` Jens Axboe
2021-06-23 23:39 ` Pavel Begunkov
2021-06-23 22:24 ` [PATCH v2 0/2] Minor SQPOLL thread fix and improvement Jens Axboe
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