[PATCH] net/core/skbuff.c fix skb_expand_head off logic error!

fix logic error!

--- linux/net/core/skbuff.c.orig 2018-04-23 20:55:37.747731000 +0800 +++ linux/net/core/skbuff.c 2018-04-23 20:56:30.782520000 +0800 @@ -1492,7 +1492,7 @@ int pskb_expand_head(struct sk_buff *skb } else { skb_free_head(skb); } - off = (data + nhead) - skb->head; + off = (skb->data - skb->head) + nhead;

skb->head = data; skb->head_frag = 0;