Re: [PATCH 2.6.30-rc5] ehea: fix invalid pointer access

From: Hannes Hering
Date: Tue May 05 2009 - 07:19:27 EST


On Tuesday 05 May 2009 11:11:27 David Howells wrote:
> Hannes Hering <hannes.hering@xxxxxxxxxxxxxxxxxx> wrote:
>
> > pref = skb_array[x];
> > - prefetchw(pref);
> > - prefetchw(pref + EHEA_CACHE_LINE);
> > + if (pref) {
> > + prefetchw(pref);
> > + prefetchw(pref + EHEA_CACHE_LINE);
>
> Ummm... Is prefetch() or prefetchw() faulting?
>
> David
Hi David,

this is an ehea driver problem, which is occuring when the receive queue runs
empty. The faulting code is more specifically the following line:

pref = (skb_array[x]->data);

Here the access to the struct element data would cause an exception.We could
have made the if block a little smaller.

Regards

Hannes
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