io_uring: fix memory leak of uid in files registration

BugLink: https://bugs.launchpad.net/bugs/1969110
commit c86d18f4aa93e0e66cda0e55827cd03eea6bc5f8 upstream.

When there are no files for __io_sqe_files_scm() to process in the
range, it'll free everything and return. However, it forgets to put uid.

Fixes: 08a451739a9b5 ("io_uring: allow sparse fixed file sets")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/accee442376f33ce8aaebb099d04967533efde92.1648226048.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 0853bd6885c2f293d88aaa7f7f1702c959b31680)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ec0b50940405f9c7b4bef00d9eca91dde370ff6d..5fc3a62eae7228df0a69adb0027bbec8588acaa0 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8130,6 +8130,7 @@ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
                        fput(fpl->fp[i]);
        } else {
                kfree_skb(skb);
+               free_uid(fpl->user);
                kfree(fpl);
        }