[IPV6]: Do not change protocol for UDPv6 sockets with pending sent data.

Signed-off-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/ipv6_sockglue.c

@@ -164,9 +164,14 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 			if (sk->sk_type == SOCK_RAW)
 				break;
 
-			if (sk->sk_protocol != IPPROTO_UDP &&
-			    sk->sk_protocol != IPPROTO_UDPLITE &&
-			    sk->sk_protocol != IPPROTO_TCP)
+			if (sk->sk_protocol == IPPROTO_UDP ||
+			    sk->sk_protocol == IPPROTO_UDPLITE) {
+				struct udp_sock *up = udp_sk(sk);
+				if (up->pending == AF_INET6) {
+					retv = -EBUSY;
+					break;
+				}
+			} else if (sk->sk_protocol != IPPROTO_TCP)
 				break;
 
 			if (sk->sk_state != TCP_ESTABLISHED) {