[PATCH 4.4 017/146] mnt: If fs_fully_visible fails call put_filesystem.

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>

commit 97c1df3e54e811aed484a036a798b4b25d002ecf upstream.

Add this trivial missing error handling.

Fixes: 1b852bceb0d1 ("mnt: Refactor the logic for mounting sysfs and proc in a user namespace")
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/namespace.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2401,8 +2401,10 @@ static int do_new_mount(struct path *pat
 			mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV;
 		}
 		if (type->fs_flags & FS_USERNS_VISIBLE) {
-			if (!fs_fully_visible(type, &mnt_flags))
+			if (!fs_fully_visible(type, &mnt_flags)) {
+				put_filesystem(type);
 				return -EPERM;
+			}
 		}
 	}