diff --git a/kernel/fork.c b/kernel/fork.c
index c9eaf20130021fbe3c8b24f4634ff7cd0ef02c3f..3561391ca450ba150256d25270dd7ae4ad339a6d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1173,10 +1173,11 @@ 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_for_children))
 		return ERR_PTR(-EINVAL);