1 files changed, 27 insertions, 20 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5944d7d668dd..f140048334ce 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,