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    SubjectRe: [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id
    [Ravikiran G Thirumalai - Tue, Aug 25, 2009 at 12:20:55PM -0700]
    | On Tue, Aug 25, 2009 at 10:31:30PM +0400, Cyrill Gorcunov wrote:
    | >[Ingo Molnar - Tue, Aug 25, 2009 at 08:15:00PM +0200]
    | >|
    | >
    | >I'm definitely not APIC expert but since I was partially involved
    | >letme turn in.
    | >
    | >Original commit which causes problem for vSMP seems to be due
    | >to cpu_has_apic bit turned off (ie due to being manually disabled
    | >or acpi table broken) so further read apic id will return plain
    | >zero (we're talking about 64 bits now). So frnakly I don't understand
    | >what is wrong with Ravikiran's patch. In case of apic disabled
    | >initial apic value will be used anyway (which is latched but
    | >actually may be changed, but it's not our case).
    | >
    | Exactly my thinking. I hoped the patch I posted solves both cases --
    | does not depend on local apic id for the "fix crash on certain UP configs"
    | case in the commit here:
    | And fixes vsmp too.
    | >Or perhaps there is an issue in srat numa nodes numbering?
    | >
    | Don't think so, local apic id has been used for for 'flat' and 'cluster'
    | apic (which was used prior to 'flat') for atleast 15 major releases.
    | Cyrill/Yinghai, can you test and confirm if the patch attached does not
    | regress the 'UP crash case' mentioned in
    | commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c please?
    | ---

    I would like to but I can;t. I don;t even know where were we hanging
    at this crash case. I was only reading commit changelog and since
    it was said about "not apic bit set" I thought about disabled apic case.

    Personally I like much more quirk Yinghai posted which leaves phys id function
    _bared_ and simple as it should be :)

    And since it's too late before kernel release -- introducing read apic back
    seems to be dangerous I suppose: there are a number of configs which could
    be having side effect. At moment they are tested _with_ Yinghai patch and
    only vSMP is issued. Though the problem need to be investigated more
    closely. But I'm not knowing that much in this area.

    -- Cyrill

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      Last update: 2009-08-25 21:43    [W:0.033 / U:8.984 seconds]
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