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* [PATCH io_uring backport to 5.13.y] io_uring: Fix race condition when sqp thread goes to sleep
@ 2021-07-25  5:07 Olivier Langlois
  2021-07-25 19:10 ` Jens Axboe
  0 siblings, 1 reply; 3+ messages in thread
From: Olivier Langlois @ 2021-07-25  5:07 UTC (permalink / raw)
  To: Jens Axboe, Pavel Begunkov, io-uring, linux-kernel, stable, gregkh

[ Upstream commit 997135017716 ("io_uring: Fix race condition when sqp thread goes to sleep") ]

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.

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
---
 fs/io_uring.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index eeea6b8c8bee..a7f1cbd7be9a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6876,7 +6876,8 @@ static int io_sq_thread(void *data)
 		}
 
 		prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
-		if (!test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state)) {
+		if (!test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) &&
+		    !io_run_task_work()) {
 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
 				io_ring_set_wakeup_flag(ctx);
 
-- 
2.32.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-07-26  7:43 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-25  5:07 [PATCH io_uring backport to 5.13.y] io_uring: Fix race condition when sqp thread goes to sleep Olivier Langlois
2021-07-25 19:10 ` Jens Axboe
2021-07-26  7:42   ` Greg KH

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