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    SubjectRe: kdump broken on 2.6.37-rc4
    On 12/16/2010 06:39 AM, Vivek Goyal wrote:
    > On Wed, Dec 15, 2010 at 08:29:01PM -0800, Yinghai Lu wrote:
    >> please check
    >>
    >> [PATCH] x86, crashkernel, 32bit: only try to get range under 512M
    >>
    >> Steanishlaw report kdump is 32bit is broken.
    >>
    >> in misc.c for decompresser, it will do sanity checking to make sure heap
    >> heap under 512M.
    >
    > Thanks Yinghai. I am wondering why on 32bit heap has to be with-in 512MB.
    > I think you are referring to following check in
    > arch/x86/boot/compressed/misc.c.
    >
    > if (end > ((-__PAGE_OFFSET-(512 <<20)-1) & 0x7fffffff))
    > error("Destination address too large");
    >
    > It was introduced here.
    >
    > commit 968de4f02621db35b8ae5239c8cfc6664fb872d8
    > Author: Eric W. Biederman <ebiederm@xmission.com>
    > Date: Thu Dec 7 02:14:04 2006 +0100
    >
    > [PATCH] i386: Relocatable kernel support
    >
    > Eric,
    >
    > It has been long. By any chance would you remember where does above
    > constraint come from?
    >

    It might, in fact, be bogus; specifically a proxy for the fact that we
    need the kernel memory including bss and brk below the lowmem boundary,
    which isn't well-defined.

    -hpa


    --
    H. Peter Anvin, Intel Open Source Technology Center
    I work for Intel. I don't speak on their behalf.



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