linux-kernel - Re: Resume Issues :Exec of NX page, Synaptics Botchup

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Date:	Mon, 23 May 2011 00:41:14 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Parag Warudkar <parag.lkml@...il.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Fenghua Yu <fenghua.yu@...el.com>,
	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Ingo Molnar <mingo@...e.hu>, Dmitry Torokhov <dtor@...l.ru>,
	linux-kernel@...r.kernel.org
Subject: Re: Resume Issues :Exec of NX page, Synaptics Botchup

On Monday, May 23, 2011, Parag Warudkar wrote:
> 
> On Sun, 22 May 2011, Linus Torvalds wrote:
> 
> > 
> > Hmm. The "Code: " line is just full of complete garbage, so I think
> > the real issue is that you really are trying to execute data.
> > 
> > And that in turn seems to be because "setup_disablecpuid()" has
> > actually been free'd, because it is marked as __init.
> > 
> > Which is fine at the initial bootup, but not so fine at resume time,
> > since it was free'd long long ago by then.
> > 
> > And it definitely shouldn' t be called at resume time. There's
> > something wrong there. That call trace is odd:
> > 
> >   Call Trace:
> >    [<ffffffff8148a119>] ? identify_cpu+0xd8/0x2d8
> >    [<ffffffff8148a32d>] identify_secondary_cpu+0x14/0x1b
> >    [<ffffffff8148bf0f>] smp_store_cpu_info+0x3c/0x3e
> >    [<ffffffff8148c2ef>] start_secondary+0xf7/0x1d2
> > 
> > because none of those should be calling "setup_disablecpuid()" at all.
> > 
> > Hmm. In fact, RIP is "setup_disablecpuid+0x40/0x40", ie it is one past
> > the _end_ of setup_disablecpuid.
> > 
> > I suspect that is actually "setup_smep()" that got called, an dthat
> > there was some garbage data in there that caused it to jump back a
> > bit.
> > 
> > Does the attached patch fix it?
> > 
> 
> Now I get a different call trace for the same NX error. (And Synaptics is 
> completely dead this time - not attributable to the patch, it was dumb 
> luck perhaps that it wored last time.)

Any chance to try with commit de5397ad5b9ad22e2401c4dacdf1bb3b19c05679
(x86, cpu: Enable/disable Supervisor Mode Execution Protection) reverted?

Rafael
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