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Date: Sun, 3 Jul 2011 14:15:49 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Kees Cook <kees.cook@canonical.com>
Cc: linux-kernel@vger.kernel.org, Len Brown <len.brown@intel.com>,
        "Rafael J. Wysocki" <rjw@sisk.pl>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Pekka Enberg <penberg@cs.helsinki.fi>, Brian Gerst <brgerst@gmail.com>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH] x86: add missing verify_cpu to 32bit wakeup
Message-ID: <20110703121549.GA21127@elf.ucw.cz>
References: <20110701211943.GA7042@outflux.net>
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Hi!

> 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.
									Pavel
-- 
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