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    SubjectRe: [PATCH] x86: add missing verify_cpu to 32bit wakeup
    On Sun 2011-07-03 12:15:22, Kees Cook wrote:
    > Hi Pavel,
    >
    > On Sun, Jul 03, 2011 at 02:15:49PM +0200, Pavel Machek wrote:
    > > > Some BIOSes will reset the Intel XD_DISABLE MSR bit when resuming from S3,
    > > > which can interact poorly with ebba638ae723d8a8fc2f7abce5ec18b688b791d7.
    > > > In 32bit PAE mode, this can lead to a fault when EFER is restored by
    > > > the kernel wakeup routines, due to it setting the NX bit for a CPU
    > > > that (thanks to the BIOS reset) now incorrectly thinks it lacks the NX
    > > > feature. 64bit wakeup already handled this through its common call path
    > > > that would hit verify_cpu(). 32bit has a separate path for restoring
    > > > CPU state on S3 wakeup, and needed to call verify_cpu() to handle this
    > > > situation.
    > > >
    > > > Signed-off-by: Kees Cook <kees.cook@canonical.com>
    > > > Cc: stable@kernel.org
    > >
    > > Looks ok to me, but I'm not sure it is stable material.
    >
    > Well, I figured anything that shipped with
    > ebba638ae723d8a8fc2f7abce5ec18b688b791d7 should get it, since it is
    > a regression in the 32bit PAE with BIOS-disabled NX corner-case.

    Aha, if it is an regression it makes sense for stable..

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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