From bf68b5b34311ee57ed40749a1257a30b46127556 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 27 Sep 2022 00:44:39 +0100 Subject: io_uring/rw: fix unexpected link breakage req->cqe.res is set in io_read() to the amount of bytes left to be done, which is used to figure out whether to fail a read or not. However, io_read() may do another without returning, and we stash the previous value into ->bytes_done but forget to update cqe.res. Then we ask a read to do strictly less than cqe.res but expect the return to be exactly cqe.res. Fix the bug by updating cqe.res for retries. Cc: stable@vger.kernel.org Reported-and-Tested-by: Beld Zhang Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/3a1088440c7be98e5800267af922a67da0ef9f13.1664235732.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/rw.c | 1 + 1 file changed, 1 insertion(+) (limited to 'io_uring/rw.c') diff --git a/io_uring/rw.c b/io_uring/rw.c index 59c92a4616b8..ed14322aadb9 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -793,6 +793,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) return -EAGAIN; } + req->cqe.res = iov_iter_count(&s->iter); /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If * we get -EIOCBQUEUED, then we'll get a notification when the -- cgit v1.2.3