linux-kernel - Re: Fwd: [Bug 150021] New: kernel panic: "kernel tried to execute NX-protected page" when resuming from hibernate to disk

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Date:	Tue, 26 Jul 2016 16:53:19 -0500
From:	Josh Poimboeuf <jpoimboe@...hat.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...e.de>,
	Pavel Machek <pavel@....cz>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>, shuzzle@...lbox.org
Subject: Re: Fwd: [Bug 150021] New: kernel panic: "kernel tried to execute
 NX-protected page" when resuming from hibernate to disk

On Tue, Jul 26, 2016 at 10:15:39PM +0200, Rafael J. Wysocki wrote:
> On Tuesday, July 26, 2016 09:39:05 AM Josh Poimboeuf wrote:
> > On Tue, Jul 26, 2016 at 01:32:28PM +0200, Rafael J. Wysocki wrote:
> > > Hi,
> > > 
> > > The following commit:
> > > 
> > > commit 13523309495cdbd57a0d344c0d5d574987af007f
> > > Author: Josh Poimboeuf <jpoimboe@...hat.com>
> > > Date:   Thu Jan 21 16:49:21 2016 -0600
> > > 
> > >     x86/asm/acpi: Create a stack frame in do_suspend_lowlevel()
> > >     
> > >     do_suspend_lowlevel() is a callable non-leaf function which doesn't
> > >     honor CONFIG_FRAME_POINTER, which can result in bad stack traces.
> > >     
> > >     Create a stack frame for it when CONFIG_FRAME_POINTER is enabled.
> > > 
> > > is reported to cause a resume-from-hibernation regression due to an attempt
> > > to execute an NX page (we've seen quite a bit of that recently).
> > > 
> > > I'm asking the reporter to try 4.7, but if the problem is still there, we'll
> > > need to revert the above I'm afraid.
> 
> So the bug is still there in 4.7 and it goes away after reverting the above
> commit.  I guess I'll send a revert then.

Hm, the code in wakeup_64.S seems quite magical, but I can't figure out
why this change causes a panic.  Is it really causing the panic or is it
uncovering some other bug?  Maybe we should hold off on reverting until
we understand the issue.

-- 
Josh