Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs mount fix from Al Viro:
 "Fix for umount -l/mount --move race caught by syzbot yesterday..."

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  do_move_mount(): fix an unsafe use of is_anon_ns()

fs/namespace.c

@@ -2599,7 +2599,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
 	if (attached && !check_mnt(old))
 		goto out;
 
-	if (!attached && !is_anon_ns(ns))
+	if (!attached && !(ns && is_anon_ns(ns)))
 		goto out;
 
 	if (old->mnt.mnt_flags & MNT_LOCKED)