diff --git a/[refs] b/[refs]
index 380be7ab56ab..edc642796e41 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b43309578477ff3271945d4efb920f558a309b4a
+refs/heads/master: 31da185d8162ae0f30a13ed945f1f4d28d158133
diff --git a/trunk/net/ipv4/netfilter/ip_conntrack_proto_tcp.c b/trunk/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
index 2b87c1974be6..721ddbf522b4 100644
--- a/trunk/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
+++ b/trunk/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
@@ -819,6 +819,7 @@ static int tcp_error(struct sk_buff *skb,
 	 */
 	/* FIXME: Source route IP option packets --RR */
 	if (hooknum == NF_IP_PRE_ROUTING
+	    && skb->ip_summed != CHECKSUM_UNNECESSARY
 	    && csum_tcpudp_magic(iph->saddr, iph->daddr, tcplen, IPPROTO_TCP,
 			         skb->ip_summed == CHECKSUM_HW ? skb->csum
 			      	 : skb_checksum(skb, iph->ihl*4, tcplen, 0))) {