io_uring: clear req->result on IOPOLL re-issue

commit 56450c20fe10d4d93f58019109aa4e06fc0b9206 upstream.

Make sure we clear req->result, which was set to -EAGAIN for retry
purposes, when moving it to the reissue list. Otherwise we can end up
retrying a request more than once, which leads to weird results in
the io-wq handling (and other spots).

Cc: stable@vger.kernel.org
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 26978630378e0c2d0dd2b02aa8aa61372833262f..b966e2b8a77dac9d1eb36cc9bd66ed687c7cd514 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1810,6 +1810,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
 
                req = list_first_entry(done, struct io_kiocb, list);
                if (READ_ONCE(req->result) == -EAGAIN) {
+                       req->result = 0;
                        req->iopoll_completed = 0;
                        list_move_tail(&req->list, &again);
                        continue;