linux-kernel - Re: [regression, bisected] x86: efi: Pass boot services variable info to runtime code

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Message-ID: <20130523222321.GB31880@sgi.com>
Date:	Thu, 23 May 2013 17:23:21 -0500
From:	Russ Anderson <rja@....com>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	Matthew Garrett <matthew.garrett@...ula.com>,
	matt.fleming@...el.com, linux-efi@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...ux.intel.com>
Subject: Re: [regression, bisected] x86: efi: Pass boot services variable
 info to runtime code

On Thu, May 23, 2013 at 12:58:01PM +0100, Matt Fleming wrote:
> On Wed, 22 May, at 11:27:47AM, Russ Anderson wrote:
> > [    6.062157] EFI Variables Facility v0.08 2004-May-17
> > [    6.067731] BUG: unable to handle kernel paging request at 000000007ca95b10
> > [    6.075519] IP: [<ffff88007dbf2140>] 0xffff88007dbf213f
> 
> This is a bit of a head scratcher. Could you paste the EFI memmap
> entries in your dmesg for the regions that cover 0x7ca95b10 and
> 0x7dbf2140?  My guess would be that they're EFI runtime code regions,
> which would at least explain why we seem to be executing code in the
> direct mapping region (0xffff8800xxxxxxxx).
> 
> Are you booting via the EFI boot stub?

Interesting data point.  The failure is on a rhel7/grub2 root.
The identical kernel on a rhel6/grub root boots.  So maybe
grub2 brings out the failure?  I suspect Fedora19/grub2 on
EFI should hit the problem (for someone looking to reproduce
it).

In both cases the kernel boot line options are the same.

-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@....com
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