diff --git a/[refs] b/[refs]
index 1af8cb6ad253..9c7c35aad6d9 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bf1c1ee88008fd639ebb5c74f0555fd414369bdc
+refs/heads/master: 52d570aabe921663a987b2e4bae2bdc411cee480
diff --git a/trunk/net/ipv4/tcp_output.c b/trunk/net/ipv4/tcp_output.c
index 32c1a972fa31..23e32c806916 100644
--- a/trunk/net/ipv4/tcp_output.c
+++ b/trunk/net/ipv4/tcp_output.c
@@ -1650,7 +1650,8 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
 
 		memcpy(skb_put(skb, next_skb_size), next_skb->data, next_skb_size);
 
-		skb->ip_summed = next_skb->ip_summed;
+		if (next_skb->ip_summed == CHECKSUM_PARTIAL)
+			skb->ip_summed = CHECKSUM_PARTIAL;
 
 		if (skb->ip_summed != CHECKSUM_PARTIAL)
 			skb->csum = csum_block_add(skb->csum, next_skb->csum, skb_size);