linux-kernel - Re: [PATCH] Revert "x86-64, init: Do not set NX bits on non-NX capable hardware"

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Message-ID: <CA+55aFx1teO9rnO8z6wVpo28JaUsqS2eDQJupUzBiGbEiHgLVg@mail.gmail.com>
Date:	Mon, 20 May 2013 11:18:16 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"H. Peter Anvin" <hpa@...ux.intel.com>
Cc:	Michal Hocko <mhocko@...e.cz>, "H. Peter Anvin" <hpa@...or.com>,
	Fernando Luis Vázquez Cao <fernando@....ntt.co.jp>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"the arch/x86 maintainers" <x86@...nel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Revert "x86-64, init: Do not set NX bits on non-NX
 capable hardware"

On Mon, May 20, 2013 at 11:13 AM, H. Peter Anvin <hpa@...ux.intel.com> wrote:
>
> Indeed.  Looks like we corrupt a random bit in memory on resume.

Well, in this case, it's probably the DEBUG_PAGEALLOC that Michal has
enabled, which causes a page fault - and then a triple fault - at
secondary CPU startup. And the triple fault then results in a reboot.
Which explains the symptoms he gets.

Without DEBUG_PAGEALLOC it ends up being "just" a single-bit corruption, yes.

             Linus
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