| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.13 144/223] io_uring: Fix race condition when sqp thread goes to sleep | Date | Mon, 26 Jul 2021 17:38:56 +0200 |
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From: Olivier Langlois <olivier@trillion01.com>
commit 997135017716c33f3405e86cca5da9567b40a08e upstream.
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.
Cc: stable@vger.kernel.org Signed-off-by: Olivier Langlois <olivier@trillion01.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d1419dc32ec6a97b453bee34dc03fa6a02797142.1624473200.git.olivier@trillion01.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- 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);
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