Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751621AbeAPSJl (ORCPT + 1 other); Tue, 16 Jan 2018 13:09:41 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:43792 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750911AbeAPSJj (ORCPT ); Tue, 16 Jan 2018 13:09:39 -0500 Date: Tue, 16 Jan 2018 19:09:33 +0100 (CET) From: Thomas Gleixner To: Joseph Salisbury cc: "Shankar, Ravi V" , "vikas.shivappa@linux.intel.com" , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Luck, Tony" , "Yu, Fenghua" , "peterz@infradead.org" , "eranian@google.com" , "ak@linux.intel.com" , "davidcc@google.com" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "1733662@bugs.launchpad.net" <1733662@bugs.launchpad.net>, "Roderick W. Smith" Subject: Re: [REGRESSION][v4.14.y][v4.15] x86/intel_rdt/cqm: Improve limbo list processing In-Reply-To: Message-ID: References: <84b8d891-6217-f56d-8ec0-313f7eb317c9@canonical.com> <159B72D0-06FE-4925-A11A-1F8A7741BF70@intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="8323329-845190218-1516126176=:2366" X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-845190218-1516126176=:2366 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8BIT On Tue, 16 Jan 2018, Joseph Salisbury wrote: > On 01/16/2018 08:32 AM, Shankar, Ravi V wrote: > > Vikas on vacation until end of the month. Fenghua will look into this > > issue. > > > > On Jan 16, 2018, at 5:09 AM, Thomas Gleixner > > wrote: > > > >> > >> Vikas, Fenghua can you please look at that ASAP? > >> > >> On Sun, 14 Jan 2018, Thomas Gleixner wrote: > >> > >>> On Fri, 12 Jan 2018, Joseph Salisbury wrote: > >>> > >>>> Hi Vikas, > >>>> > >>>> A kernel bug report was opened against Ubuntu [0].? After a kernel > >>>> bisect, it was found that reverting the following commit resolved > >>>> this bug: > >>>> > >>>> commit 24247aeeabe99eab13b798ccccc2dec066dd6f07 > >>>> Author: Vikas Shivappa >>>> > > >>>> Date:?? Tue Aug 15 18:00:43 2017 -0700 > >>>> > >>>> ??? x86/intel_rdt/cqm: Improve limbo list processing > >>>> > >>>> > >>>> The regression was introduced as of v4.14-r1 and still exists with > >>>> current mainline.? The trace with v4.15-rc7 is in comment #44[1]. > >>>> > >>>> I was hoping to get your feedback, since you are the patch author.? Do > >>>> you think gathering any additional data will help diagnose this issue, > >>>> or would it be best to submit a revert request? > >>> > >>> That stinks like a use after free. Can you run with KASAN enabled? > >>> > >>> Thanks, > >>> > >>> ? ?tglx > > > Here is some data wiht KASAN enabled: > https://bugs.launchpad.net/ubuntu/+source/linux-hwe/+bug/1733662/comments/51 > > Are there any specific logs you would like to see, or specific actions > executed? No, the KASAN output is pretty clear where the issue is. Thanks, tglx --8323329-845190218-1516126176=:2366--