[IPV6]: Make sure errors propagate properly in {udp,raw} sendmsg.

net/ipv6/ip6_output.c

@@ -209,7 +209,6 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 	int seg_len = skb->len;
 	int hlimit;
 	u32 mtu;
-	int err = 0;
 
 	if (opt) {
 		int head_room;

net/ipv6/raw.c

@@ -659,7 +659,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg
 		fl.oif = np->mcast_oif;
 
 	dst = ip6_dst_lookup(sk, &fl);
-	if (dst->error)
+	if ((err = dst->error))
 		goto out;
 
 	if (hlimit < 0) {

net/ipv6/udp.c

@@ -811,8 +811,10 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg
 		 * The socket lock must be held while it's corked.
 		 */
 		lock_sock(sk);
-		if (likely(up->pending))
+		if (likely(up->pending)) {
+			dst = NULL;
 			goto do_append_data;
+		}
 		release_sock(sk);
 	}
 	ulen += sizeof(struct udphdr);
@@ -929,7 +931,7 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg
 		fl.oif = np->mcast_oif;
 
 	dst = ip6_dst_lookup(sk, &fl);
-	if (dst->error)
+	if ((err = dst->error))
 		goto out;
 
 	if (hlimit < 0) {
@@ -968,6 +970,7 @@ static int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg
 	else if (!corkreq)
 		err = udp_v6_push_pending_frames(sk, up);
 
+	if (dst)
 		ip6_dst_store(sk, dst,
 			      !ipv6_addr_cmp(&fl.fl6_dst, &np->daddr) ?
 			      &np->daddr : NULL);