1 files changed, 27 insertions, 20 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5944d7d..f140048 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -560,15 +560,11 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 						 __be16 sport, __be16 dport,
 						 struct udp_table *udptable)
 {
-	struct sock *sk;
 	const struct iphdr *iph = ip_hdr(skb);
 
-	if (unlikely(sk = skb_steal_sock(skb)))
-		return sk;
-	else
-		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
-					 iph->daddr, dport, inet_iif(skb),
-					 udptable);
+	return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
+				 iph->daddr, dport, inet_iif(skb),
+				 udptable);
 }
 
 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
@@ -999,7 +995,7 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 			err = PTR_ERR(rt);
 			rt = NULL;
 			if (err == -ENETUNREACH)
-				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+				IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 			goto out;
 		}
 
@@ -1098,6 +1094,9 @@ int udp_sendpage(struct sock *sk, struct page *page, int offset,
 	struct udp_sock *up = udp_sk(sk);
 	int ret;
 
+	if (flags & MSG_SENDPAGE_NOTLAST)
+		flags |= MSG_MORE;
+
 	if (!up->pending) {
 		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
 
@@ -1236,7 +1235,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 	bool slow;
 
 	if (flags & MSG_ERRQUEUE)
-		return ip_recv_error(sk, msg, len);
+		return ip_recv_error(sk, msg, len, addr_len);
 
 try_again:
 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
@@ -1600,12 +1599,16 @@ static void flush_stack(struct sock **stack, unsigned int count,
 		kfree_skb(skb1);
 }
 
-static void udp_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
+/* For TCP sockets, sk_rx_dst is protected by socket lock
+ * For UDP, we use xchg() to guard against concurrent changes.
+ */
+static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
 {
-	struct dst_entry *dst = skb_dst(skb);
+	struct dst_entry *old;
 
 	dst_hold(dst);
-	sk->sk_rx_dst = dst;
+	old = xchg(&sk->sk_rx_dst, dst);
+	dst_release(old);
 }
 
 /*
@@ -1736,15 +1739,16 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	if (udp4_csum_init(skb, uh, proto))
 		goto csum_error;
 
-	if (skb->sk) {
+	sk = skb_steal_sock(skb);
+	if (sk) {
+		struct dst_entry *dst = skb_dst(skb);
 		int ret;
-		sk = skb->sk;
 
-		if (unlikely(sk->sk_rx_dst == NULL))
-			udp_sk_rx_dst_set(sk, skb);
+		if (unlikely(sk->sk_rx_dst != dst))
+			udp_sk_rx_dst_set(sk, dst);
 
 		ret = udp_queue_rcv_skb(sk, skb);
-
+		sock_put(sk);
 		/* a return value > 0 means to resubmit the input, but
 		 * it wants the return to be -protocol, or 0
 		 */
@@ -1910,17 +1914,20 @@ static struct sock *__udp4_lib_demux_lookup(struct net *net,
 
 void udp_v4_early_demux(struct sk_buff *skb)
 {
-	const struct iphdr *iph = ip_hdr(skb);
-	const struct udphdr *uh = udp_hdr(skb);
+	struct net *net = dev_net(skb->dev);
+	const struct iphdr *iph;
+	const struct udphdr *uh;
 	struct sock *sk;
 	struct dst_entry *dst;
-	struct net *net = dev_net(skb->dev);
 	int dif = skb->dev->ifindex;
 
 	/* validate the packet */
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
 		return;
 
+	iph = ip_hdr(skb);
+	uh = udp_hdr(skb);
+
 	if (skb->pkt_type == PACKET_BROADCAST ||
 	    skb->pkt_type == PACKET_MULTICAST)
 		sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,