From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: Fwd: [Bug 150021] New: kernel panic: "kernel tried to execute NX-protected page" when resuming from hibernate to disk Date: Thu, 28 Jul 2016 01:29:49 +0200 Message-ID: <1670639.GCDubuBUSI@vostro.rjw.lan> References: <16541580.dFLT14ScxF@vostro.rjw.lan> <20160727221738.ilmm6mnvlmzmvfnt@treble> <1703386.0Oti4h65x8@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from cloudserver094114.home.net.pl ([79.96.170.134]:52146 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932335AbcG0XYp (ORCPT ); Wed, 27 Jul 2016 19:24:45 -0400 In-Reply-To: <1703386.0Oti4h65x8@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Josh Poimboeuf Cc: "Rafael J. Wysocki" , Ingo Molnar , Borislav Petkov , Pavel Machek , Linux PM list , Linux Kernel Mailing List , Thomas Gleixner , shuzzle@mailbox.org On Thursday, July 28, 2016 01:20:53 AM Rafael J. Wysocki wrote: > On Wednesday, July 27, 2016 05:17:38 PM Josh Poimboeuf wrote: > > On Thu, Jul 28, 2016 at 12:12:15AM +0200, Rafael J. Wysocki wrote: > > > On Wednesday, July 27, 2016 12:59:18 PM Josh Poimboeuf wrote: > > > > Hm... I have a theory, but I'm not sure about it. I noticed that > > > > x86_acpi_enter_sleep_state(), > > > > > > I think you mean x86_acpi_suspend_lowlevel(). > > > > Oops! > > > > > > which is involved in suspend, overwrites > > > > several global variables (e.g, initial_code) which are used by the CPU > > > > boot code in head_64.S. But surprisingly, it doesn't restore those > > > > variables to their original values after it resumes. > > > > > > Is the head_64.S code also used to bring up offline CPUs? > > > > Yes. > > OK > > So it is really interesting why and how that stuff works for everybody. > > Basically, CPU online should fail after a suspend-resume cycle, but it > doesn't most of the time AFAICS. do_boot_cpu() restores those values, so I think we're safe from that angle. That should apply to the CPU online during resume from hibernation too. Thanks, Rafael