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| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-09-27 00:44:39 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-09-26 18:44:15 -0600 |
| commit | bf68b5b34311ee57ed40749a1257a30b46127556 (patch) | |
| tree | 2f99ab4a5d2c2c7f29bfd836573ab44aa87973ae /io_uring | |
| parent | 4c17a496a7a0730fdfc9e249b83cc58249111532 (diff) | |
| download | linux-stable-bf68b5b34311ee57ed40749a1257a30b46127556.tar.gz linux-stable-bf68b5b34311ee57ed40749a1257a30b46127556.tar.bz2 linux-stable-bf68b5b34311ee57ed40749a1257a30b46127556.zip | |
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 <beldzhang@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3a1088440c7be98e5800267af922a67da0ef9f13.1664235732.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/rw.c | 1 |
1 files changed, 1 insertions, 0 deletions
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 |