diff --git a/kernel/fork.c b/kernel/fork.c
index d7eb727..adbea16 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -841,6 +841,8 @@
 	atomic_set(&sig->live, 1);
 	init_waitqueue_head(&sig->wait_chldexit);
 	sig->flags = 0;
+	if (clone_flags & CLONE_NEWPID)
+		sig->flags |= SIGNAL_UNKILLABLE;
 	sig->group_exit_code = 0;
 	sig->group_exit_task = NULL;
 	sig->group_stop_count = 0;