Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 6.0 013/862] io_uring/rw: fix unexpected link breakage | Date | Wed, 19 Oct 2022 10:21:40 +0200 |
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From: Pavel Begunkov <asml.silence@gmail.com>
commit bf68b5b34311ee57ed40749a1257a30b46127556 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- io_uring/rw.c | 1 + 1 file changed, 1 insertion(+)
--- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -823,6 +823,7 @@ int io_read(struct io_kiocb *req, unsign 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
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