[src/trunk]: src/sys/kern sigactsunshare(): set reference count in a case of ...

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

details:   https://anonhg.NetBSD.org/src/rev/e51392a7feba
branches:  trunk
changeset: 750420:e51392a7feba
user:      rmind <rmind%NetBSD.org@localhost>
date:      Wed Dec 30 23:31:56 2009 +0000

description:
sigactsunshare(): set reference count in a case of new sigacts allocation.
Bug (e.g. memory leak) can happen when using clone(2) call.

diffstat:

 sys/kern/kern_sig.c |  38 +++++++++++++++++---------------------
 1 files changed, 17 insertions(+), 21 deletions(-)

diffs (74 lines):

diff -r 3714b09995bd -r e51392a7feba sys/kern/kern_sig.c
--- a/sys/kern/kern_sig.c       Wed Dec 30 23:23:58 2009 +0000
+++ b/sys/kern/kern_sig.c       Wed Dec 30 23:31:56 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_sig.c,v 1.301 2009/12/20 04:49:09 rmind Exp $     */
+/*     $NetBSD: kern_sig.c,v 1.302 2009/12/30 23:31:56 rmind Exp $     */
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.301 2009/12/20 04:49:09 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.302 2009/12/30 23:31:56 rmind Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_compat_sunos.h"
@@ -230,24 +230,19 @@
 struct sigacts *
 sigactsinit(struct proc *pp, int share)
 {
-       struct sigacts *ps, *ps2;
+       struct sigacts *ps = pp->p_sigacts, *ps2;
 
-       ps = pp->p_sigacts;
-
-       if (share) {
+       if (__predict_false(share)) {
                atomic_inc_uint(&ps->sa_refcnt);
-               ps2 = ps;
-       } else {
-               ps2 = pool_cache_get(sigacts_cache, PR_WAITOK);
-               /* XXXAD get rid of this */
-               mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED);
-               mutex_enter(&ps->sa_mutex);
-               memcpy(&ps2->sa_sigdesc, ps->sa_sigdesc,
-                   sizeof(ps2->sa_sigdesc));
-               mutex_exit(&ps->sa_mutex);
-               ps2->sa_refcnt = 1;
+               return ps;
        }
+       ps2 = pool_cache_get(sigacts_cache, PR_WAITOK);
+       mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED);
+       ps2->sa_refcnt = 1;
 
+       mutex_enter(&ps->sa_mutex);
+       memcpy(ps2->sa_sigdesc, ps->sa_sigdesc, sizeof(ps2->sa_sigdesc));
+       mutex_exit(&ps->sa_mutex);
        return ps2;
 }
 
@@ -259,15 +254,16 @@
 void
 sigactsunshare(struct proc *p)
 {
-       struct sigacts *ps, *oldps;
+       struct sigacts *ps, *oldps = p->p_sigacts;
 
-       oldps = p->p_sigacts;
-       if (oldps->sa_refcnt == 1)
+       if (__predict_true(oldps->sa_refcnt == 1))
                return;
+
        ps = pool_cache_get(sigacts_cache, PR_WAITOK);
-       /* XXXAD get rid of this */
        mutex_init(&ps->sa_mutex, MUTEX_DEFAULT, IPL_SCHED);
-       memset(&ps->sa_sigdesc, 0, sizeof(ps->sa_sigdesc));
+       memset(ps->sa_sigdesc, 0, sizeof(ps->sa_sigdesc));
+       ps->sa_refcnt = 1;
+
        p->p_sigacts = ps;
        sigactsfree(oldps);
 }