Re: [tip:x86/mm] x86: make e820_update_range() handle small rangeupdate

[Ingo Molnar]

* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> > 
> >> Ingo Molnar wrote:
> >>> * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> >>>
> >>>> Commit-ID:  78a8b35bc7abf8b8333d6f625e08c0f7cc1c3742
> >>>> Gitweb:     http://git.kernel.org/tip/78a8b35bc7abf8b8333d6f625e08c0f7cc1c3742
> >>>> Author:     Yinghai Lu <yinghai@xxxxxxxxxx>
> >>>> AuthorDate: Thu, 12 Mar 2009 22:36:01 -0700
> >>>> Commit:     Ingo Molnar <mingo@xxxxxxx>
> >>>> CommitDate: Sat, 14 Mar 2009 12:20:07 +0100
> >>>>
> >>>> x86: make e820_update_range() handle small range update
> >>>>
> >>>> Impact: enhance e820 code to handle more cases
> >>>>
> >>>> Try to handle new range which could be covered by one entry.
> >>>>
> >>>> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> >>>> Cc: jbeulich@xxxxxxxxxx
> >>>> LKML-Reference: <49B9F0C1.10402@xxxxxxxxxx>
> >>>> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> >>> -tip testing found a bootup crash + reboot due to this patch.
> >>>
> >>> config attached. The bootup crashes here:
> >>>
> >>> [    0.000000] MTRR variable ranges enabled:
> >>> [    0.000000]   0 base 0000000000 mask FFC0000000 write-back
> >>> [    0.000000]   1 disabled
> >>> [    0.000000]   2 disabled
> >>> [    0.000000]   3 disabled
> >>> [    0.000000]   4 disabled
> >>> [    0.000000]   5 disabled
> >>> [    0.000000]   6 disabled
> >>> [    0.000000]   7 disabled
> >>> [    0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
> >>> [    0.000000]   get_mtrr: cpu0 reg00 base=0000000000 size=0000040000 write-back
> >>> [    reboot  ]
> >>>
> >> what does the e820 map look like?
> > 
> > [    0.000000] BIOS-provided physical RAM map:
> > [    0.000000]  BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
> > [    0.000000]  BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
> > [    0.000000]  BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
> > [    0.000000]  BIOS-e820: 0000000000100000 - 000000003fff0000 (usable)
> > [    0.000000]  BIOS-e820: 000000003fff0000 - 000000003fff3000 (ACPI NVS)
> > [    0.000000]  BIOS-e820: 000000003fff3000 - 0000000040000000 (ACPI data)
> > [    0.000000]  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
> > [    0.000000]  BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
> > 
> 
> it seems that patch revealed the bug in 
> setup_bios_corruption_check

Cool. I'm wondering, could this explain:

   http://bugzilla.kernel.org/show_bug.cgi?id=12645

?

	Ingo
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