[NETNS]: icmp(v6)_sk should not pin a namespace.

So, change icmp(v6)_sk creation/disposal to the scheme used in the
netlink for rtnl, i.e. create a socket in the context of the init_net
and assign the namespace without getting a referrence later.

Also use sk_release_kernel instead of sock_release to properly destroy
such sockets.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 3368f32..3eb594d 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -802,6 +802,8 @@
 		}
 
 		__icmpv6_sk[i] = sk = sock->sk;
+		sk_change_net(sk, &init_net);
+
 		sk->sk_allocation = GFP_ATOMIC;
 		/*
 		 * Split off their lock-class, because sk->sk_dst_lock
@@ -831,11 +833,8 @@
 	return 0;
 
  fail:
-	for (j = 0; j < i; j++) {
-		if (!cpu_possible(j))
-			continue;
-		sock_release(__icmpv6_sk[j]->sk_socket);
-	}
+	for (j = 0; j < i; j++)
+		sk_release_kernel(__icmpv6_sk[j]);
 
 	return err;
 }
@@ -845,7 +844,7 @@
 	int i;
 
 	for_each_possible_cpu(i) {
-		sock_release(__icmpv6_sk[i]->sk_socket);
+		sk_release_kernel(__icmpv6_sk[i]);
 	}
 	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 }