linux-kernel - Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data)

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Date:	Fri, 24 Dec 2010 18:26:44 +0100
From:	matthieu castet <castet.matthieu@...e.fr>
To:	Lin Ming <ming.m.lin@...el.com>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Siarhei Liakh <sliakh.lkml@...il.com>,
	Xuxian Jiang <jiang@...ncsu.edu>, Ingo Molnar <mingo@...e.hu>,
	Arjan van de Ven <arjan@...radead.org>,
	lkml <linux-kernel@...r.kernel.org>, tglx <tglx@...utronix.de>
Subject: Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection
 for kernel data)

Hi,

Le Tue, 30 Nov 2010 13:00:30 +0800,
Lin Ming <ming.m.lin@...el.com> a écrit :

> On Sat, 2010-11-27 at 01:31 +0800, mat wrote:
> > Le Tue, 23 Nov 2010 23:55:27 +0100,
> > mat <castet.matthieu@...e.fr> a écrit :
> > 
> > > Le Mon, 22 Nov 2010 17:42:47 +0100,
> > > Andi Kleen <andi@...stfloor.org> a écrit :
> > > 
> > > > > That seems to be a S3 specific code path, that won't fix
> > > > > anything. Simply do:
> > > > > 
> > > > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > > > > 
> > > > > and your machine will explode..
> > > > 
> > > > The SMP startup trampoline is copied I believe
> > > > and only executed in real mode without page tables.
> > > > 
> > > > So it's perhaps not the trampoline, but the early startup 
> > > > code that ends up being broken.
> > > yes :
> > > acpi wakeup code and smp trampoline are copied in low memory
> > > (first 1MB).
> > > 
> > > So they can't end up int the kernel data mapping ?
> > > 
> > > So it should something else.
> > > 
> > > I will try to investigate on this.
> > > 
> > Unfortunately on my laptop supporting NX, suspend to ram seems
> > broken (even without this patch) and I got only one core, so I am
> > unable to test it.
> > 
> > Does cpu suspend/resume is broken ? Or it is only S3 ?
> > 
> > If yes, are there any interesting trace if we suspend only one core
> > with sysfs.
> 
> echo 0 > /sys/devices/system/cpu/cpu1/online;
> echo 1 > /sys/devices/system/cpu/cpu1/online;
> 
> then machine just reboots...
> 
Ok,

could you try the attached patch ?

Thanks

Matthieu

View attachment "x64_nx_data.diff" of type "text/x-patch" (896 bytes)