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Date: Tue, 15 Apr 2008 20:31:08 -0700 (PDT)
Message-Id: <20080415.203108.55491723.davem@davemloft.net>
To: tonyb@cybernetics.com
Cc: mcarlson@broadcom.com, herbert@gondor.apana.org.au, mchan@broadcom.com,
       netdev@vger.kernel.org, gregkh@suse.de, linux-kernel@vger.kernel.org
Subject: Re: TG3 network data corruption regression 2.6.24/2.6.23.4
From: David Miller <davem@davemloft.net>
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From: Tony Battersby <tonyb@cybernetics.com>
Date: Tue, 15 Apr 2008 11:39:27 -0400

> Thanks, your patch fixes the problem (tested on 2.6.24.4).  However, I
> had to change "(skb->mac_header & 3)" in your patch to "((long)
> skb->mac_header & 3)" since mac_header is a pointer rather than an int
> on 32-bit systems.
> 
> Tested-by: Tony Battersby <tonyb@cybernetics.com>

Thanks for testing.

Matt, skb->mac_header is either a pointer or an integer offset
depending upon whether we are building 32-bit or 64-bit.

Testing skb->mac_header is therefore wrong, because it's an
offset from a pointer in the 64-bit case and therefore it's
alignment does not indicate correctly the actual final alignment
of skb->head + skb->max_header.

Therefore you should test skb_mac_header(skb) and cast it with
(unsigned long).

Please respin this fix with that correction so I can apply it
and get this bug fixed, thanks!