From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751519AbdHaHbc (ORCPT ); Thu, 31 Aug 2017 03:31:32 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58705 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457AbdHaHba (ORCPT ); Thu, 31 Aug 2017 03:31:30 -0400 Message-Id: <20170831073053.111536870@linutronix.de> User-Agent: quilt/0.63-1 Date: Thu, 31 Aug 2017 09:16:00 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Andrew Morton , Borislav Petkov , Sebastian Siewior , Nicholas Piggin , Don Zickus , Chris Metcalf , Ulrich Obergfell Subject: [patch 02/29] perf/x86/intel: Sanitize PMU HT bug workaround References: <20170831071558.995235362@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=perf-x86-intel--Sanitize-PMU-HT-bug-workaround.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra The lockup_detector_suspend/resume() interface is broken in several ways especially as it results in recursive locking of the CPU hotplug lock. Use the new stop/restart interface in the perf NMI watchdog to temporarily disable and reenable the already active watchdog events. That's enough to handle it. Signed-off-by: Peter Zijlstra Signed-off-by: Thomas Gleixner --- arch/x86/events/intel/core.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -4318,10 +4318,9 @@ static __init int fixup_ht_bug(void) return 0; } - if (lockup_detector_suspend() != 0) { - pr_debug("failed to disable PMU erratum BJ122, BV98, HSD29 workaround\n"); - return 0; - } + cpus_read_lock(); + + hardlockup_detector_perf_stop(); x86_pmu.flags &= ~(PMU_FL_EXCL_CNTRS | PMU_FL_EXCL_ENABLED); @@ -4329,9 +4328,7 @@ static __init int fixup_ht_bug(void) x86_pmu.commit_scheduling = NULL; x86_pmu.stop_scheduling = NULL; - lockup_detector_resume(); - - cpus_read_lock(); + hardlockup_detector_perf_restart(); for_each_online_cpu(c) free_excl_cntrs(c);