skb_tail_pointer(skb) not work correctly. And point the udp header tail wrongly

Question

On linux kernerl version 3.2.48.

As an udp server in kernel mod, skb_tail_pointer(skb) is not correct, it point the udp header tail, lossing the payload size. udphdr->len is right.

It is strange.

Answer 1

it is possible that tail and data pointer points to the same location. skb_tail_pointer() return the starting tail address.