X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=net%2Fipv4%2Fudp.c;h=1b8c5ba7d5f732ea2220ada929049c5c7cfd5e83;hb=10e2eb878f3ca07ac2f05fa5ca5e6c4c9174a27a;hp=83aa604f9273c332c5a0e5399253d961ef92eb9a;hpb=2fc09962e24ace45154d0c16024f1eb15700f3e8;p=karo-tx-linux.git

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 83aa604f9273..1b8c5ba7d5f7 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1995,12 +1995,19 @@ void udp_v4_early_demux(struct sk_buff *skb)
 
 	skb->sk = sk;
 	skb->destructor = sock_efree;
-	dst = sk->sk_rx_dst;
+	dst = READ_ONCE(sk->sk_rx_dst);
 
 	if (dst)
 		dst = dst_check(dst, 0);
-	if (dst)
-		skb_dst_set_noref(skb, dst);
+	if (dst) {
+		/* DST_NOCACHE can not be used without taking a reference */
+		if (dst->flags & DST_NOCACHE) {
+			if (likely(atomic_inc_not_zero(&dst->__refcnt)))
+				skb_dst_set(skb, dst);
+		} else {
+			skb_dst_set_noref(skb, dst);
+		}
+	}
 }
 
 int udp_rcv(struct sk_buff *skb)