udp: increment UDP_MIB_INERRORS if copy failed

In UDP recvmsg(), we miss an increase of UDP_MIB_INERRORS if the copy
of skb to userspace failed for whatever reason.

Reported-by: Shawn Bohrer <[e-mail]>
Signed-off-by: Eric Dumazet <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/udp.c

···
 
 	if (unlikely(err)) {
 		trace_kfree_skb(skb, udp_recvmsg);
+		if (!peeked) {
+			atomic_inc(&sk->sk_drops);
+			UDP_INC_STATS_USER(sock_net(sk),
+					   UDP_MIB_INERRORS, is_udplite);
+		}
 		goto out_free;
 	}
 

net/ipv6/udp.c

···
 	}
 	if (unlikely(err)) {
 		trace_kfree_skb(skb, udpv6_recvmsg);
+		if (!peeked) {
+			atomic_inc(&sk->sk_drops);
+			if (is_udp4)
+				UDP_INC_STATS_USER(sock_net(sk),
+						   UDP_MIB_INERRORS,
+						   is_udplite);
+			else
+				UDP6_INC_STATS_USER(sock_net(sk),
+						    UDP_MIB_INERRORS,
+						    is_udplite);
+		}
 		goto out_free;
 	}
 	if (!peeked) {