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

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

From: Eric W. Biederman <redacted>

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" <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/fs/namespace.c
+++ b/fs/namespace.c

@@ -2409,8 +2409,10 @@ 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;
+			}
 		}
 	}