From: Pavel Begunkov <asml.silence@xxxxxxxxx> commit 59850d226e4907a6f37c1d2fe5ba97546a8691a4 upstream. Checking !list_empty(&ctx->cq_overflow_list) around noflush in io_cqring_events() is racy, because if it fails but a request overflowed just after that, io_cqring_overflow_flush() still will be called. Remove the second check, it shouldn't be a problem for performance, because there is cq_check_overflow bit check just above. Cc: <stable@xxxxxxxxxxxxxxx> # 5.5+ Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2242,7 +2242,7 @@ static unsigned io_cqring_events(struct * we wake up the task, and the next invocation will flush the * entries. We cannot safely to it from here. */ - if (noflush && !list_empty(&ctx->cq_overflow_list)) + if (noflush) return -1U; io_cqring_overflow_flush(ctx, false, NULL, NULL);
