From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: 2.6.38.1 general protection fault
Date: Mon, 28 Mar 2011 19:54:37 +0200
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Cc: Tomasz Chmielewski <mangoo@wpkg.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
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Hello everyone,

On Mon, Mar 28, 2011 at 11:19:51AM +0200, Avi Kivity wrote:
> On 03/28/2011 08:24 AM, Tomasz Chmielewski wrote:
> > On 27.03.2011 11:42, Avi Kivity wrote:
> >
> > (...)
> >
> >> Okay, the fork came from the ,script=.
> >>
> >> The issue with %rsi looks like a use-after-free, however
> >> kvm_mmu_notifier_invalidate_range_start appears to be properly srcu
> >> protected.
> >
> > FYI, I saw this one as well:
> >
> > http://www.virtall.com/files/temp/kvm.txt
> 
> Similar pattern - top 16 bits of %rsi are flipped.
> 
> Marcelo, what was the option to enable padding for allocations and 
> overrun detection?  Also use-after-free?

BTW, is it genuine that a protection fault is generated instead of a page
fault while dereferencing address 0x00008805d6b087f8? I would normally
except a page fault from a memory dereference that doesn't alter
processor state/segments.

The other GFP happened in pmdp_clear_flush_notify inside
collapse_huge_page.