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From: Olivier Langlois <olivier@trillion01.com>
To: Jens Axboe <axboe@kernel.dk>,
	Pavel Begunkov <asml.silence@gmail.com>,
	io-uring@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Olivier Langlois <olivier@trillion01.com>
Subject: [PATCH 1/2] io_uring: Fix race condition when sqp thread goes to sleep
Date: Tue, 22 Jun 2021 11:45:20 -0700	[thread overview]
Message-ID: <67c806d0bcf2e096c1b0c7e87bd5926c37231b87.1624387080.git.olivier@trillion01.com> (raw)
In-Reply-To: <cover.1624387080.git.olivier@trillion01.com>

If an asynchronous completion happens before the task is preparing
itself to wait and set its state to TASK_INTERRUPTABLE, the completion
will not wake up the sqp thread.

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..02f789e07d4c 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) && !current->task_works) {
 			needs_sched = true;
 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
 				io_ring_set_wakeup_flag(ctx);
-- 
2.32.0


  reply	other threads:[~2021-06-22 18:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-22 18:45 [PATCH 0/2] Minor SQPOLL thread fix and improvement Olivier Langlois, Olivier Langlois
2021-06-22 18:45 ` Olivier Langlois [this message]
2021-06-22 18:53   ` [PATCH 1/2] io_uring: Fix race condition when sqp thread goes to sleep Olivier Langlois
2021-06-22 18:55     ` Pavel Begunkov
2021-06-22 19:07       ` Olivier Langlois
     [not found]   ` <60d23218.1c69fb81.79e86.f345SMTPIN_ADDED_MISSING@mx.google.com>
2021-06-22 20:45     ` [PATCH 1/2 v2] " Pavel Begunkov
2021-06-22 22:37       ` Olivier Langlois
2021-06-22 22:42         ` Olivier Langlois
2021-06-22 23:03           ` Pavel Begunkov
2021-06-23 13:52             ` Olivier Langlois
2021-06-23 15:58               ` Pavel Begunkov
2021-06-22 18:45 ` [PATCH 2/2] io_uring: Create define to modify a SQPOLL parameter Olivier Langlois
2021-06-22 20:58   ` Pavel Begunkov

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