diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 3b9cd487075a..5c58e21f724e 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -524,7 +524,6 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 	int tunnel_hlen;
 	int version;
 	int nhoff;
-	int thoff;
 
 	tun_info = skb_tunnel_info(skb);
 	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
@@ -558,10 +557,16 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 	    (ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
 		truncate = true;
 
-	thoff = skb_transport_header(skb) - skb_mac_header(skb);
-	if (skb->protocol == htons(ETH_P_IPV6) &&
-	    (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff))
-		truncate = true;
+	if (skb->protocol == htons(ETH_P_IPV6)) {
+		int thoff;
+
+		if (skb_transport_header_was_set(skb))
+			thoff = skb_transport_header(skb) - skb_mac_header(skb);
+		else
+			thoff = nhoff + sizeof(struct ipv6hdr);
+		if (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff)
+			truncate = true;
+	}
 
 	if (version == 1) {
 		erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 4e37f7c29900..a9051df0625d 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -939,7 +939,6 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
 	__be16 proto;
 	__u32 mtu;
 	int nhoff;
-	int thoff;
 
 	if (!pskb_inet_may_pull(skb))
 		goto tx_err;
@@ -960,10 +959,16 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
 	    (ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
 		truncate = true;
 
-	thoff = skb_transport_header(skb) - skb_mac_header(skb);
-	if (skb->protocol == htons(ETH_P_IPV6) &&
-	    (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff))
-		truncate = true;
+	if (skb->protocol == htons(ETH_P_IPV6)) {
+		int thoff;
+
+		if (skb_transport_header_was_set(skb))
+			thoff = skb_transport_header(skb) - skb_mac_header(skb);
+		else
+			thoff = nhoff + sizeof(struct ipv6hdr);
+		if (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff)
+			truncate = true;
+	}
 
 	if (skb_cow_head(skb, dev->needed_headroom ?: t->hlen))
 		goto tx_err;