[src/trunk]: src/sys/netinet6 Prevent in6_ifaddr from being freed with holdin...

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fe785743391c
branches:  trunk
changeset: 820602:fe785743391c
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Thu Jan 12 04:43:59 2017 +0000

description:
Prevent in6_ifaddr from being freed with holding its psref

This is a possible fix for PR kern/51828.

diffstat:

 sys/netinet6/in6.c |  14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diffs (50 lines):

diff -r 3c156aa1fe56 -r fe785743391c sys/netinet6/in6.c
--- a/sys/netinet6/in6.c        Thu Jan 12 02:00:42 2017 +0000
+++ b/sys/netinet6/in6.c        Thu Jan 12 04:43:59 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: in6.c,v 1.232 2017/01/11 18:25:46 christos Exp $       */
+/*     $NetBSD: in6.c,v 1.233 2017/01/12 04:43:59 ozaki-r Exp $        */
 /*     $KAME: in6.c,v 1.198 2001/07/18 09:12:38 itojun Exp $   */
 
 /*
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.232 2017/01/11 18:25:46 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.233 2017/01/12 04:43:59 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -797,6 +797,9 @@
        int dad_delay, was_tentative;
        struct in6_ifaddr *ia = iap ? *iap : NULL;
 
+       KASSERT((iap == NULL && psref == NULL) ||
+           (iap != NULL && psref != NULL));
+
        in6m_sol = NULL;
 
        /* Validate parameters */
@@ -950,8 +953,6 @@
                ia->ia_ifp = ifp;
                IN6_ADDRLIST_ENTRY_INIT(ia);
                ifa_psref_init(&ia->ia_ifa);
-               if (psref)
-                       ia6_acquire(ia, psref);
        }
 
        /* update timestamp */
@@ -1300,8 +1301,11 @@
                nd6_dad_start(&ia->ia_ifa, dad_delay + 1);
        }
 
-       if (iap)
+       if (iap != NULL) {
                *iap = ia;
+               if (hostIsNew)
+                       ia6_acquire(ia, psref);
+       }
 
        return 0;