linux-kernel - Re: [PATCH v3 1/2] x86/AMD: Fix cpu_llc

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Date:   Mon, 7 Nov 2016 10:20:31 +0100
From:   Borislav Petkov <bp@...e.de>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     x86@...nel.org, Yazen Ghannam <Yazen.Ghannam@....com>,
        linux-kernel@...r.kernel.org,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH v3 1/2] x86/AMD: Fix cpu_llc_id for AMD Fam17h systems

On Mon, Nov 07, 2016 at 08:31:21AM +0100, Ingo Molnar wrote:
> > cpu_llc_id (Last Level Cache ID) derivation on AMD Fam17h has an
> > underflow bug when extracting the socket_id value. It starts from 0

How's this...

> > so subtracting 1 from it will result in an invalid value. This breaks
> > scheduling topology later on since the cpu_llc_id will be incorrect.
   ^^^^^^^^^^^^^^^^^^^
... here?

> Same question as for the previous patch: what are the effects of the bug:

See above.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--