diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index fc1835c6bb40..8af3461d18d2 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -251,7 +251,7 @@ batadv_frag_merge_packets(struct hlist_head *chain, struct sk_buff *skb)
 	kfree(entry);
 
 	/* Make room for the rest of the fragments. */
-	if (pskb_expand_head(skb_out, 0, size - skb->len, GFP_ATOMIC) < 0) {
+	if (pskb_expand_head(skb_out, 0, size - skb_out->len, GFP_ATOMIC) < 0) {
 		kfree_skb(skb_out);
 		skb_out = NULL;
 		goto free;