diff --git a/kernel/fork.c b/kernel/fork.c
index ffbc0904794e..80d92e987f21 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1171,10 +1171,11 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 		return ERR_PTR(-EINVAL);
 
 	/*
-	 * If the new process will be in a different pid namespace
-	 * don't allow the creation of threads.
+	 * If the new process will be in a different pid namespace don't
+	 * allow it to share a thread group or signal handlers with the
+	 * forking task.
 	 */
-	if ((clone_flags & (CLONE_VM|CLONE_NEWPID)) &&
+	if ((clone_flags & (CLONE_SIGHAND | CLONE_NEWPID)) &&
 	    (task_active_pid_ns(current) != current->nsproxy->pid_ns))
 		return ERR_PTR(-EINVAL);