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From: David Miller <davem@davemloft.net>
Subject: Re: SKB truesize bug
Date: Thu, 20 Nov 2008 04:03:11 -0800 (PST)
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From: Kostya B <bkostya@hotmail.com>
Date: Thu, 20 Nov 2008 11:59:28 +0000

> Perhaps we should take a closer look on pskb_expand_head()
> 
> And add 
> 
> +skb->truesize = size + sizeof(struct sk_buff);

You can't.  If a socket is attached to the skb it's buffer
accounting will get corrupted if you modify skb->truesize.

This has been explained a thousand times on this list.