I fear just installing those won't help me that much as long as there is
nothing that is really done. Ok, I hope this will work as intended. The
problem is that while it is clear that the pointer used to call the
destructor in free_hot_cold_page() is wrong, it does not help much
explaining how things got there.

Looking at the code there are only about four places that use this
foreign page flag: gnttab, netback, pageattr_64-xen and pgtable_32-xen.
Now netback should not be used as we are domU and pageattr_64 should not
matter as the instance is a 32bit. Not really sure about gnttab. But
there are other places using page->index and maybe something goes wrong
there (though the likely candidate pgrable_32 only uses the flag for pte
pages and those should not get used otherwise).

So what I did is to rename the element index of the page structure and
convert all users to s that indirectly through function calls. Then to
have a independent element to additionally store the destructor and
finally a check whenever index is set whether this would compromise the
destructor.

I added v2 kernel images to my people page. If things go as I hope,
those should emit a warning whenever the destructor seems to get
overwritten. Probably still leading to a crash later because the page
should not have had a destructor at all... Unfortunately I cannot verify
whether I did it right as I cannot trigger the problem.

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https://bugs.launchpad.net/bugs/705562

Title:
  ami-6836dc01 8.04 32 bit AMI kernel lock bug

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