ipvs: null check of net->ipvs in lblc(r) shedulers

Avoid crash when registering shedulers after
the IPVS core initialization for netns fails. Do this by
checking for present core (net->ipvs).

Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

net/netfilter/ipvs/ip_vs_lblc.c

@@ -551,6 +551,9 @@ static int __net_init __ip_vs_lblc_init(struct net *net)
 {
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
+	if (!ipvs)
+		return -ENOENT;
+
 	if (!net_eq(net, &init_net)) {
 		ipvs->lblc_ctl_table = kmemdup(vs_vars_table,
 						sizeof(vs_vars_table),

net/netfilter/ipvs/ip_vs_lblcr.c

@@ -745,6 +745,9 @@ static int __net_init __ip_vs_lblcr_init(struct net *net)
 {
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
+	if (!ipvs)
+		return -ENOENT;
+
 	if (!net_eq(net, &init_net)) {
 		ipvs->lblcr_ctl_table = kmemdup(vs_vars_table,
 						sizeof(vs_vars_table),