diff --git a/[refs] b/[refs]
index eecae529a075..6b2a2a652c10 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: af4b8a83add95ef40716401395b44a1b579965f4
+refs/heads/master: 225778d68d98e7cfe2579f8d8b2d7b76f8541b8b
diff --git a/trunk/kernel/pid_namespace.c b/trunk/kernel/pid_namespace.c
index 3cc29b830e9e..0dbbc66b6ec6 100644
--- a/trunk/kernel/pid_namespace.c
+++ b/trunk/kernel/pid_namespace.c
@@ -146,6 +146,8 @@ struct pid_namespace *copy_pid_ns(unsigned long flags,
 		return get_pid_ns(old_ns);
 	if (flags & (CLONE_THREAD|CLONE_PARENT))
 		return ERR_PTR(-EINVAL);
+	if (task_active_pid_ns(current) != old_ns)
+		return ERR_PTR(-EINVAL);
 	return create_pid_namespace(user_ns, old_ns);
 }