diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 24ffc5e..ba46769 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -589,7 +589,7 @@
 #endif
 	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
 				      ip_hdr(skb)->saddr, /* XXX */
-				      sizeof(struct tcphdr), IPPROTO_TCP, 0);
+				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
 	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
 	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 424d9c4..e8b0fdd 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1012,14 +1012,14 @@
 	}
 #endif
 
-	buff->csum = csum_partial((char *)t1, sizeof(*t1), 0);
+	buff->csum = csum_partial((char *)t1, tot_len, 0);
 
 	memset(&fl, 0, sizeof(fl));
 	ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 	ipv6_addr_copy(&fl.fl6_src, &ipv6_hdr(skb)->daddr);
 
 	t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
-				    sizeof(*t1), IPPROTO_TCP,
+				    tot_len, IPPROTO_TCP,
 				    buff->csum);
 
 	fl.proto = IPPROTO_TCP;