Re: [B.A.T.M.A.N.] [PATCH 2/3] batman-adv: Receive fragmented packets and merge

On Wed, Apr 24, 2013 at 03:17:26AM +0800, Marek Lindner wrote:

On Sunday, April 21, 2013 00:17:33 Martin Hundebøll wrote:

...

• /* Make room for the rest of the fragments. */
• if (pskb_expand_head(skb_out, 0, size - skb->len, GFP_ATOMIC) < 0) {

• kfree_skb(skb_out);
  

• goto free;
  

• }

If pskb_expand_head() really fails this function will lead to a crash because skb_out points to undefined memory.

I'm not sure about this. pskb_expand_head() can only fail in the early phase and in that case it seems to return the original skb as it was.

Btw, is pskb_expand_head() enough to handle all cases ? Did you try this with a large (4000 bytes or more) packet ?

I don't personally see any problem with this. But maybe I am overlooking something..however, proper testing will make everybody happy :P