Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756625AbdIHRQh (ORCPT ); Fri, 8 Sep 2017 13:16:37 -0400 Received: from ud10.udmedia.de ([194.117.254.50]:37770 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752265AbdIHRQg (ORCPT ); Fri, 8 Sep 2017 13:16:36 -0400 Date: Fri, 8 Sep 2017 19:16:33 +0200 From: Markus Trippelsdorf To: Andy Lutomirski Cc: Ingo Molnar , Borislav Petkov , Thomas Gleixner , Peter Zijlstra , LKML , Ingo Molnar , Tom Lendacky Subject: Re: Current mainline git (24e700e291d52bd2) hangs when building e.g. perf Message-ID: <20170908171633.GA279@x4> References: <20170907062845.GA280@x4> <20170908053534.GA276@x4> <20170908080536.ninspvplibd37fj2@pd.tnic> <20170908091614.nmdxjnukxowlsjja@pd.tnic> <20170908094815.GA278@x4> <20170908103513.npjmb2kcjt2zljb2@gmail.com> <20170908103906.GB278@x4> <20170908113039.GA285@x4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2268 Lines: 60 On 2017.09.08 at 09:12 -0700, Andy Lutomirski wrote: > On Fri, Sep 8, 2017 at 4:30 AM, Markus Trippelsdorf > wrote: > > On 2017.09.08 at 12:39 +0200, Markus Trippelsdorf wrote: > >> On 2017.09.08 at 12:35 +0200, Ingo Molnar wrote: > >> > > >> > * Markus Trippelsdorf wrote: > >> > > >> > > On 2017.09.08 at 11:16 +0200, Borislav Petkov wrote: > >> > > > On Fri, Sep 08, 2017 at 10:05:36AM +0200, Borislav Petkov wrote: > >> > > > > On Fri, Sep 08, 2017 at 08:26:44AM +0200, Thomas Gleixner wrote: > >> > > > > > On Fri, 8 Sep 2017, Markus Trippelsdorf wrote: > >> > > > > > > >> > > > > > CC+ Borislav. He might have access to such a beast > >> > > > > > >> > > > > Can I have /proc/cpuinfo and dmesg pls, in order to see whether I have > >> > > > > something similar? > >> > > > > > >> > > > > Private mail's fine too. > >> > > > > >> > > > So I don't have exactly your model - mine is model 2, stepping 3 but I see > >> > > > something strange too, in dmesg: > >> > > > >> > > I'm pretty sure the bug is in the merged 'x86-mm-for-linus' branch: > >> > > Either Andy's "PCID optimized TLB flushing" (would be my guess) or > >> > > 'encrypted memory' support by Tom Lendacky. > >> > > > >> > > (Bisecting is hard, because sometimes I can compile stuff for over 15 > >> > > minutes without hitting the bug. At other times the machine locks up > >> > > hard when starting X11 already.) > >> > > >> > Do you have the 72c0098d92ce fix? > >> > >> Yes. The bug still happens on the current git tree (which has the fix > >> already): > > > > The bug is definitely caused by Andy Lutomirski's PCID optimized TLB > > flushing" patches. Tom is off the hook. > > I'm pretty sure it can't be PCID per se, since these CPUs are way too > old and are very unlikely to have PCID. Yes, the CPU doesn't support PCID (,but it does support PGE). > It could plausibly be the lazy TLB flushing changes. Yes, I've narrowed it down to: commit 94b1b03b519b81c494900cb112aa00ed205cc2d9 Author: Andy Lutomirski Date: Thu Jun 29 08:53:17 2017 -0700 x86/mm: Rework lazy TLB mode and TLB freshness tracking Theoretically you guys should be able to reproduce the issue by using the "nopcid" boot option. -- Markus