From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757122AbcGZWhb (ORCPT ); Tue, 26 Jul 2016 18:37:31 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:41443 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754198AbcGZWh2 (ORCPT ); Tue, 26 Jul 2016 18:37:28 -0400 From: "Rafael J. Wysocki" To: Josh Poimboeuf Cc: Ingo Molnar , Borislav Petkov , Pavel Machek , Linux PM list , Linux Kernel Mailing List , Thomas Gleixner , shuzzle@mailbox.org Subject: Re: Fwd: [Bug 150021] New: kernel panic: "kernel tried to execute NX-protected page" when resuming from hibernate to disk Date: Wed, 27 Jul 2016 00:42:30 +0200 Message-ID: <4852923.iQFmCCTKQM@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.5.0-rc1+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20160726215319.twz22r5kbkpsgzfg@treble> References: <16541580.dFLT14ScxF@vostro.rjw.lan> <1931457.H9nCOt9KIt@vostro.rjw.lan> <20160726215319.twz22r5kbkpsgzfg@treble> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, July 26, 2016 04:53:19 PM Josh Poimboeuf wrote: > 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 > > > > 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? It doesn't matter really. It surely interacts with something in a really odd way, but that only means that its impact goes far beyond what was expected when it was applied. Its changelog is inadequate as a result and so on. > Maybe we should hold off on reverting until we understand the issue. Which very well may take forever. And AFAICS this is a fix for a theoretical issue and it *reliably* triggers a very practical kernel panic for this particular reporter. I'd rather live with the theoretical issue unfixed to be honest. Thanks, Rafael