[src/trunk]: src/sys/net Protect vlan_unconfig with a mutex

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

details:   https://anonhg.NetBSD.org/src/rev/0654b7ddf0fa
branches:  trunk
changeset: 332892:0654b7ddf0fa
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Sat Oct 11 10:16:49 2014 +0000

description:
Protect vlan_unconfig with a mutex

It is not thread-safe but is likely to be executed in concurrent.
See PR 49264 for more detail.

diffstat:

 sys/net/if_vlan.c |  16 +++++++++++++---
 1 files changed, 13 insertions(+), 3 deletions(-)

diffs (66 lines):

diff -r 73a47c2b4b83 -r 0654b7ddf0fa sys/net/if_vlan.c
--- a/sys/net/if_vlan.c Sat Oct 11 10:06:15 2014 +0000
+++ b/sys/net/if_vlan.c Sat Oct 11 10:16:49 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_vlan.c,v 1.75 2014/10/09 04:48:12 ozaki-r Exp $     */
+/*     $NetBSD: if_vlan.c,v 1.76 2014/10/11 10:16:49 ozaki-r Exp $     */
 
 /*-
  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
@@ -78,7 +78,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.75 2014/10/09 04:48:12 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.76 2014/10/11 10:16:49 ozaki-r Exp $");
 
 #include "opt_inet.h"
 
@@ -91,6 +91,7 @@
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/kauth.h>
+#include <sys/mutex.h>
 
 #include <net/bpf.h>
 #include <net/if.h>
@@ -180,6 +181,8 @@
 /* XXX This should be a hash table with the tag as the basis of the key. */
 static LIST_HEAD(, ifvlan) ifv_list;
 
+static kmutex_t ifv_mtx __cacheline_aligned;
+
 struct if_clone vlan_cloner =
     IF_CLONE_INITIALIZER("vlan", vlan_clone_create, vlan_clone_destroy);
 
@@ -191,6 +194,7 @@
 {
 
        LIST_INIT(&ifv_list);
+       mutex_init(&ifv_mtx, MUTEX_DEFAULT, IPL_NONE);
        if_clone_attach(&vlan_cloner);
 }
 
@@ -359,8 +363,12 @@
 {
        struct ifvlan *ifv = ifp->if_softc;
 
-       if (ifv->ifv_p == NULL)
+       mutex_enter(&ifv_mtx);
+
+       if (ifv->ifv_p == NULL) {
+               mutex_exit(&ifv_mtx);
                return;
+       }
 
        /*
         * Since the interface is being unconfigured, we need to empty the
@@ -412,6 +420,8 @@
        if_down(ifp);
        ifp->if_flags &= ~(IFF_UP|IFF_RUNNING);
        ifp->if_capabilities = 0;
+
+       mutex_exit(&ifv_mtx);
 }
 
 /*