Re: 2.6.19, more unwinder problems ...

From: Ingo Molnar
Date: Fri Dec 15 2006 - 06:27:32 EST



* Jan Beulich <jbeulich@xxxxxxxxxx> wrote:

> validating that the item read is between current and previous stack
> pointer, which in turn are being derived from register state and
> unwind information.

i still dont quite get it - and i feel deja vu. Didnt we agree that the
right way to go about this is to validate all stack information based on
what the kernel already knows about all the stacks that the task may
use? I.e. only allow pointers into the kernel stack and into the various
kernel stacks. No 'probe kernel pointer' or anything. If the unwind data
or register state ever points outside that basic filter, abandon the
walk. Am i missing something?

Ingo
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