[src/trunk]: src/sys/kern When delivering a signal, it's possible that the pr...

[pgoyette <pgoyette%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c3a33d90f6c9
branches:  trunk
changeset: 811103:c3a33d90f6c9
user:      pgoyette <pgoyette%NetBSD.org@localhost>
date:      Tue Oct 13 07:00:59 2015 +0000

description:
When delivering a signal, it's possible that the process's state in
p_stat is SACTIVE yet p_sflag is PS_STOPPING (while waiting for other
lwp's to stop).  In that case, we don't want to adjust the parent's
p_nstopchild count.

Found by Robert Elz.

XXX Pullups to: NetBSD-7, -6{,-0,-1}, and -5{,-0,-1,-2}

diffstat:

 sys/kern/kern_sig.c |  13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diffs (37 lines):

diff -r 1da01d60439f -r c3a33d90f6c9 sys/kern/kern_sig.c
--- a/sys/kern/kern_sig.c       Tue Oct 13 06:47:21 2015 +0000
+++ b/sys/kern/kern_sig.c       Tue Oct 13 07:00:59 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_sig.c,v 1.320 2015/10/02 16:54:15 christos Exp $  */
+/*     $NetBSD: kern_sig.c,v 1.321 2015/10/13 07:00:59 pgoyette 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 1.320 2015/10/02 16:54:15 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.321 2015/10/13 07:00:59 pgoyette Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_dtrace.h"
@@ -1359,14 +1359,13 @@
                }
                if ((prop & SA_CONT) != 0 || signo == SIGKILL) {
                        /*
-                        * Re-adjust p_nstopchild if the process wasn't
-                        * collected by its parent.
+                        * Re-adjust p_nstopchild if the process was
+                        * stopped but not yet collected by its parent.
                         */
+                       if (p->p_stat == SSTOP && !p->p_waited)
+                               p->p_pptr->p_nstopchild--;
                        p->p_stat = SACTIVE;
                        p->p_sflag &= ~PS_STOPPING;
-                       if (!p->p_waited) {
-                               p->p_pptr->p_nstopchild--;
-                       }
                        if (p->p_slflag & PSL_TRACED) {
                                KASSERT(signo == SIGKILL);
                                goto deliver;