ipvs: fix oops in ip_vs_dst_event on rmmod

	After commit 39f618b4fd95ae243d940ec64c961009c74e3333 (3.4)
"ipvs: reset ipvs pointer in netns" we can oops in
ip_vs_dst_event on rmmod ip_vs because ip_vs_control_cleanup
is called after the ipvs_core_ops subsys is unregistered and
net->ipvs is NULL. Fix it by exiting early from ip_vs_dst_event
if ipvs is NULL. It is safe because all services and dests
for the net are already freed.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index d43e3c122f7bdc5b042b92ce74981149922faa78..84444dda194b61806efaeadde4c2458f502d8283 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1521,11 +1521,12 @@ static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
 {
        struct net_device *dev = ptr;
        struct net *net = dev_net(dev);
+       struct netns_ipvs *ipvs = net_ipvs(net);
        struct ip_vs_service *svc;
        struct ip_vs_dest *dest;
        unsigned int idx;
 
-       if (event != NETDEV_UNREGISTER)
+       if (event != NETDEV_UNREGISTER || !ipvs)
                return NOTIFY_DONE;
        IP_VS_DBG(3, "%s() dev=%s\n", __func__, dev->name);
        EnterFunction(2);
@@ -1551,7 +1552,7 @@ static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
                }
        }
 
-       list_for_each_entry(dest, &net_ipvs(net)->dest_trash, n_list) {
+       list_for_each_entry(dest, &ipvs->dest_trash, n_list) {
                __ip_vs_dev_reset(dest, dev);
        }
        mutex_unlock(&__ip_vs_mutex);