From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751455AbdIOMy6 (ORCPT ); Fri, 15 Sep 2017 08:54:58 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45942 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751335AbdIOMy5 (ORCPT ); Fri, 15 Sep 2017 08:54:57 -0400 Date: Fri, 15 Sep 2017 14:54:43 +0200 (CEST) From: Thomas Gleixner To: kernel test robot cc: LKP , LKML , Don Zickus , Ingo Molnar , wfg@linux.intel.com, Peter Zijlstra Subject: Re: d57108d4f6 ("watchdog/core: Get rid of the thread .."): BUG: unable to handle kernel NULL pointer dereference at 0000000000000208 In-Reply-To: Message-ID: References: <59baf8db.Rfy+1ZsQ37PfCiRH%fengguang.wu@intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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 On Fri, 15 Sep 2017, Thomas Gleixner wrote: > On Fri, 15 Sep 2017, kernel test robot wrote: > > [ 0.035023] CPU: Intel Common KVM processor (family: 0xf, model: 0x6, stepping: 0x1) > > [ 0.042302] Performance Events: unsupported Netburst CPU model 6 no PMU driver, software events only. > > Cute. So there is no supported PMU, but for some unknown reason the lockup > detector can create an event, otherwise the perf availaibility check in > lockup_detector_init() would fail .... > > Peter??? In my VM the corresponding dmesg is: [ 0.038086] Performance Events: unsupported p6 CPU model 61 no PMU driver, software events only. [ 0.041031] Hierarchical SRCU implementation. [ 0.046210] NMI watchdog: Perf event create on CPU 0 failed with -2 [ 0.046980] NMI watchdog: Perf NMI watchdog permanetely disabled Confused From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0620134438734946869==" MIME-Version: 1.0 From: Thomas Gleixner To: lkp@lists.01.org Subject: Re: d57108d4f6 ("watchdog/core: Get rid of the thread .."): BUG: unable to handle kernel NULL pointer dereference at 0000000000000208 Date: Fri, 15 Sep 2017 14:54:43 +0200 Message-ID: In-Reply-To: List-Id: --===============0620134438734946869== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Fri, 15 Sep 2017, Thomas Gleixner wrote: > On Fri, 15 Sep 2017, kernel test robot wrote: > > [ 0.035023] CPU: Intel Common KVM processor (family: 0xf, model: 0x6= , stepping: 0x1) > > [ 0.042302] Performance Events: unsupported Netburst CPU model 6 no = PMU driver, software events only. > = > Cute. So there is no supported PMU, but for some unknown reason the lockup > detector can create an event, otherwise the perf availaibility check in > lockup_detector_init() would fail .... > = > Peter??? In my VM the corresponding dmesg is: [ 0.038086] Performance Events: unsupported p6 CPU model 61 no PMU drive= r, software events only. [ 0.041031] Hierarchical SRCU implementation. [ 0.046210] NMI watchdog: Perf event create on CPU 0 failed with -2 [ 0.046980] NMI watchdog: Perf NMI watchdog permanetely disabled Confused --===============0620134438734946869==--