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@vger.kernel.org # 5.5+ Signed-off-by: Pavel Begunkov asml.silence@gmail.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 b1ba9a738315..f707caed9f79 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2246,7 +2246,7 @@ static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush) * 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);