ipvs: fix oops in ip_vs_dst_event on rmmod

commit 283283c4da91adc44b03519f434ee1e7e91d6fdb upstream.

	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>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 9528ea0f859bf6a450019c812af9f5f756a8d6cb..d75eb390bda0e392e5cba62ba52854991d3819b1 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1520,11 +1520,12 @@ 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);
@@ -1550,7 +1551,7 @@ 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);