From 71e32edd2210d0304e93ac110814b5a4b3a81dc0 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 12 Sep 2021 06:45:07 -0600 Subject: [PATCH] io_uring: ensure symmetry in handling iter types in loop_rw_iter() commit 16c8d2df7ec0eed31b7d3b61cb13206a7fb930cc upstream. When setting up the next segment, we check what type the iter is and handle it accordingly. However, when incrementing and processed amount we do not, and both iter advance and addr/len are adjusted, regardless of type. Split the increment side just like we do on the setup side. Fixes: 4017eb91a9e7 ("io_uring: make loop_rw_iter() use original user supplied pointers") Cc: stable@vger.kernel.org Reported-by: Valentina Palmiotti Reviewed-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index c5d4638f6d7fd..e5698b3beb0e0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3107,12 +3107,15 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter) ret = nr; break; } + if (!iov_iter_is_bvec(iter)) { + iov_iter_advance(iter, nr); + } else { + req->rw.len -= nr; + req->rw.addr += nr; + } ret += nr; if (nr != iovec.iov_len) break; - req->rw.len -= nr; - req->rw.addr += nr; - iov_iter_advance(iter, nr); } return ret;