Re: [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id

From: Ingo Molnar
Date: Tue Aug 25 2009 - 15:34:29 EST



* Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx> wrote:

> On Tue, Aug 25, 2009 at 11:50:56AM -0700, Yinghai Lu wrote:
> >Cyrill Gorcunov wrote:
> >
> >initial apic id and apic id could be different.
> >
> >and we should use initial apic id to get correct phys pkg id in case BIOS set crazy apic id.
> >
>
> Is there a specific bug we are fixing here? Again, this behavior
> was present from atleast 2.6.15-2.6.30 on 'flat' and older
> 'cluster' apics, and intel documentation suggests local apic be
> used. Is there a specific bios bug that is being fixed?
>
> (The BIOS is not supposed to set a crazy apic ID. The BIOS is
> buggy in that case -- Quoting section 9.4.6 from Intel System
> programming guide vol 3A part 1:

That means very little. If Yinghai fixed a real bug in an existing
system we should consider it. Yinghai?

Ingo
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