diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 2160d5d009cb6e97f36f3b4319322fb52a354866..3815e8505ed2a3be767dae4ec9822d2152c4e72e 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -456,7 +456,8 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 	memmove(head->head + sizeof(struct frag_hdr), head->head,
 		(head->data - head->head) - sizeof(struct frag_hdr));
-	head->mac_header += sizeof(struct frag_hdr);
+	if (skb_mac_header_was_set(head))
+		head->mac_header += sizeof(struct frag_hdr);
 	head->network_header += sizeof(struct frag_hdr);
 
 	skb_reset_transport_header(head);