From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id F14DEC5CFF1 for ; Tue, 12 Jun 2018 07:51:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB91420693 for ; Tue, 12 Jun 2018 07:51:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB91420693 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933592AbeFLHvt (ORCPT ); Tue, 12 Jun 2018 03:51:49 -0400 Received: from mga03.intel.com ([134.134.136.65]:47405 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933242AbeFLHvr (ORCPT ); Tue, 12 Jun 2018 03:51:47 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jun 2018 00:51:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,213,1526367600"; d="scan'208";a="56615820" Received: from black.fi.intel.com (HELO black.fi.intel.com.) ([10.237.72.28]) by FMSMGA003.fm.intel.com with ESMTP; 12 Jun 2018 00:51:45 -0700 From: Alexander Shishkin To: Peter Zijlstra , Ingo Molnar Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, jolsa@redhat.com, Alexander Shishkin Subject: [PATCH v1 1/6] perf: Disable PMU around address filter adjustment Date: Tue, 12 Jun 2018 10:51:12 +0300 Message-Id: <20180612075117.65420-2-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180612075117.65420-1-alexander.shishkin@linux.intel.com> References: <20180612075117.65420-1-alexander.shishkin@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the PMU is used for AUX data sampling, the hardware event that triggers it may come in during a critical section of address filters adjustment (if it's delivered as NMI) and in turn call the address filter sync code, causing a spinlock recursion. To prevent this, disable the PMU around these critical sections, so that AUX sampling won't take place there. Signed-off-by: Alexander Shishkin --- kernel/events/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 4e1a1bf8d867..0f5cd1b08dbd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6299,6 +6299,12 @@ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) if (!has_addr_filter(event)) return; + /* + * if sampling kicks in in the critical section, + * we risk spinlock recursion on the ifh::lock + */ + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (filter->inode) { @@ -6313,6 +6319,8 @@ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + if (restart) perf_event_stop(event, 1); } @@ -6993,6 +7001,8 @@ static void __perf_addr_filters_adjust(struct perf_event *event, void *data) if (!file) return; + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (perf_addr_filter_match(filter, file, off, @@ -7008,6 +7018,8 @@ static void __perf_addr_filters_adjust(struct perf_event *event, void *data) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + if (restart) perf_event_stop(event, 1); } @@ -8261,6 +8273,8 @@ static void perf_event_addr_filters_apply(struct perf_event *event) down_read(&mm->mmap_sem); + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { event->addr_filters_offs[count] = 0; @@ -8279,6 +8293,8 @@ static void perf_event_addr_filters_apply(struct perf_event *event) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + up_read(&mm->mmap_sem); mmput(mm); -- 2.17.1