Re: [GIT PULL] x86/uapi for 3.8

["H. Peter Anvin" <hpa@zytor.com>]

On 12/15/2012 10:35 AM, Linus Torvalds wrote:
> On Sat, Dec 15, 2012 at 8:33 AM, Markus Trippelsdorf
> <markus@trippelsdorf.de> wrote:
>> On 2012.12.14 at 17:47 -0800, Linus Torvalds wrote:
>>>
>>> Ho humm. Anybody else see anything strange?
>>
>> Yes. I'm seeing a BUG early during boot on my machine (RIP=NULL):
>>
>>  BUG: unable to handle kernel NULL pointer dereference at           (null)
>>
>> This is caused by commit 53b87cf088e2 ("x86, mm: Include the
>> entire kernel memory map in trampoline_pgd")
> 
> Hmm. That reverts cleanly, and the result boots fine for me. And the
> commit looks like exactly the kind of thing that could result in
> problems with exactly the right memory layout, so it could explain why
> the bisect failed and some kernels randomly worked for me and others
> didn't.
> 
> So this at least looks like a very possible candidate.
> 
> Does anybody have an explanation for the problem?
> 
> Btw. the machine in question does not have EFI, and is a bog-standard
> PC (DMI string: "P7H57D-V EVO, BIOS 0999 01/19/2010")
> 
> Matt? Jan?
> 

Matt is on vacation, and I'm partly offline for the weekend, but that
definitely seems suspicious.  Do we have a memory map of the affected
machine(s)?

	-hpa