--- kernel/bsd/kern/kern_fork.c	2018/04/24 18:26:01	1.1
+++ kernel/bsd/kern/kern_fork.c	2018/04/24 18:27:42	1.1.1.2
@@ -361,3 +361,9 @@ uthread_free(uthread)
 	zfree(u_thread_zone, (vm_offset_t) uthread);
 }
 	
+void
+uarea_zero(uthr)
+	struct uthread	*uthr;
+{
+	bzero(uthr, sizeof(struct uthread));
+}