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Date: Fri, 9 May 2008 21:48:39 +0100 (BST)
From: Hugh Dickins <hugh@veritas.com>
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To: Venki Pallipadi <venkatesh.pallipadi@intel.com>
cc: Ingo Molnar <mingo@elte.hu>, Frans Pop <elendil@planet.nl>,
       Jesse Barnes <jesse.barnes@intel.com>, linux-kernel@vger.kernel.org,
       "Packard, Keith" <keith.packard@intel.com>,
       Yinghai Lu <yhlu.kernel@gmail.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
       Nick Piggin <npiggin@suse.de>, Jesse Barnes <jbarnes@virtuousgeek.org>
Subject: Re: [git head] X86_PAT & mprotect
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On Fri, 9 May 2008, Venki Pallipadi wrote:
> 
> There is a defect in mprotect, which lets the user to change the page
> cache type bits by-passing the kernel reserve_memtype and free_memtype
> wrappers. Fix the problem by not letting mprotect change the PAT bits.
> 
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> Signed-off-by: Hugh Dickins <hugh@veritas.com>

Thanks a lot for finalizing that, Venki: looks good to me.
I didn't originally sign-off my version of your patch, but am happy
to do so now that you've gone over it again and fixed the pte_modify
issue (though I'm not sure what the order of our signoffs should be).

I shall need to cover the MAP_PRIVATE COW issue in do_wp_page,
but I think that's better done as a separate patch: I'll attend
to it in a few days, it's not something that will upset anyone
bisecting, my mind is elsewhere at present.

Hugh