Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

===================================================================
RCS file: /ftp/cvs/cvsroot/src/sys/kern/kern_sig.c,v
rcsdiff: /ftp/cvs/cvsroot/src/sys/kern/kern_sig.c,v: warning: Unknown phrases like `commitid ...;' are present.
retrieving revision 1.343
retrieving revision 1.344
diff -u -p -r1.343 -r1.344
--- src/sys/kern/kern_sig.c	2018/05/06 13:40:51	1.343
+++ src/sys/kern/kern_sig.c	2018/05/16 00:42:15	1.344
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_sig.c,v 1.343 2018/05/06 13:40:51 kamil Exp $	*/
+/*	$NetBSD: kern_sig.c,v 1.344 2018/05/16 00:42:15 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.343 2018/05/06 13:40:51 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.344 2018/05/16 00:42:15 kamil Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_dtrace.h"
@@ -1720,10 +1720,10 @@ issignal(struct lwp *l)
 		 * If traced, always stop, and stay stopped until released
 		 * by the debugger.  If the our parent is our debugger waiting
 		 * for us and we vforked, don't hang as we could deadlock.
-		 *
-		 * XXX: support PT_TRACE_ME called after vfork(2)
 		 */
-		if ((p->p_slflag & PSL_TRACED) != 0 && signo != SIGKILL) {
+		if (ISSET(p->p_slflag, PSL_TRACED) && signo != SIGKILL &&
+		    !(ISSET(p->p_lflag, PL_PPWAIT) &&
+		     (p->p_pptr == p->p_opptr))) {
 			/*
 			 * Take the signal, but don't remove it from the
 			 * siginfo queue, because the debugger can send