From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: mac80211 truesize bugs
Date: Thu, 01 May 2008 03:32:21 -0700 (PDT)
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From: Johannes Berg <johannes@sipsolutions.net>
Date: Thu, 01 May 2008 12:08:14 +0200

> > Grrr, I bet it's coming from a combination of the
> > skb_set_mac_header(skb, 0); call done by mac80211 and the skb_push()
> > calls in net/packet/af_packet.c
> > 
> > davem@sunset:~/src/GIT/net-2.6$ egrep skb_push net/packet/af_packet.c
> > 	skb_push(skb, skb->data - skb_mac_header(skb));
> > 			skb_push(skb, skb->data - skb_mac_header(skb));
> > 			skb_push(skb, skb->data - skb_mac_header(skb));
> 
> But mac80211 does set_mac_header(0) so this should just push zero bytes,
> no?

Right you are.

So, I wonder what's causing the problem...  Could you "remember" the
length and truesize at the skb_orphan() point in mac80211, right
after the skb_push(), then in the truesize warning, print those
"remembered" values as well as the current ones.