From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754433AbcHXM3g (ORCPT ); Wed, 24 Aug 2016 08:29:36 -0400 Received: from mga14.intel.com ([192.55.52.115]:39334 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751774AbcHXM3f (ORCPT ); Wed, 24 Aug 2016 08:29:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,570,1464678000"; d="scan'208";a="1019600978" From: Alexander Shishkin To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel@vger.kernel.org, vince@deater.net, eranian@google.com, Arnaldo Carvalho de Melo Subject: Re: [PATCH 1/3] perf/x86/intel/bts: Fix confused ordering of PMU callbacks In-Reply-To: <1471942474-1854-2-git-send-email-alexander.shishkin@linux.intel.com> References: <1471942474-1854-1-git-send-email-alexander.shishkin@linux.intel.com> <1471942474-1854-2-git-send-email-alexander.shishkin@linux.intel.com> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Wed, 24 Aug 2016 15:28:22 +0300 Message-ID: <87mvk2l5ax.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexander Shishkin writes: > The intel_bts driver is using a cpu-local 'started' variable to order > callbacks and PMIs and make sure that AUX transactions don't get messed > up. However, the ordering rules in regard to this variable is a complete > mess, which recently resulted in perf_fuzzer-triggered warnings and > panics. > > The general ordering rule that is patch is enforcing is that this > cpu-local variable be set only when the cpu-local AUX transaction is > active; consequently, this variable is to be checked before the AUX > related bits can be touched. > > Signed-off-by: Alexander Shishkin Ok, this one is broken, please disregard. Regards, -- Alex