From bccc78a590be19ba3e2857b412568d36fd234194 Mon Sep 17 00:00:00 2001
From: christos <christos@NetBSD.org>
Date: Thu, 2 Feb 2012 02:44:06 +0000
Subject: [PATCH] Disable PTRACE_FORK for vforked() children, because the
 parent is waiting and will not receive the SIGTRAP in time.

---
 sys/kern/kern_fork.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index f3c3aa20014f..5815b90fd2ae 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_fork.c,v 1.186 2011/09/02 20:06:29 christos Exp $	*/
+/*	$NetBSD: kern_fork.c,v 1.187 2012/02/02 02:44:06 christos Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.186 2011/09/02 20:06:29 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.187 2012/02/02 02:44:06 christos Exp $");
 
 #include "opt_ktrace.h"
 
@@ -460,8 +460,12 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	LIST_INSERT_HEAD(&parent->p_children, p2, p_sibling);
 	p2->p_exitsig = exitsig;		/* signal for parent on exit */
 
+	/*
+	 * We don't want to tracefork vfork()ed processes because they
+	 * will not receive the SIGTRAP until it is too late.
+	 */
 	tracefork = (p1->p_slflag & (PSL_TRACEFORK|PSL_TRACED)) ==
-	    (PSL_TRACEFORK|PSL_TRACED);
+	    (PSL_TRACEFORK|PSL_TRACED) && (flags && FORK_PPWAIT) == 0;
 	if (tracefork) {
 		p2->p_slflag |= PSL_TRACED;
 		p2->p_opptr = p2->p_pptr;