From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753068AbdKVXAC (ORCPT ); Wed, 22 Nov 2017 18:00:02 -0500 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:24552 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752711AbdKVW02 (ORCPT ); Wed, 22 Nov 2017 17:26:28 -0500 From: alexander.levin@verizon.com Cc: Peter Zijlstra , Linus Torvalds , Thomas Gleixner , "Ingo Molnar" , alexander.levin@verizon.com X-Host: mariner.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.14 17/51] perf/core: Fix __perf_read_group_add() locking Thread-Topic: [PATCH AUTOSEL for 4.14 17/51] perf/core: Fix __perf_read_group_add() locking Thread-Index: AQHTY+DT7BXF9xSd0ke5yELPVNdzpg== Date: Wed, 22 Nov 2017 22:25:40 +0000 Message-ID: <20171122222526.20021-17-alexander.levin@verizon.com> References: <20171122222526.20021-1-alexander.levin@verizon.com> In-Reply-To: <20171122222526.20021-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMN0ibq032313 From: Peter Zijlstra [ Upstream commit a9cd8194e1e6bd09619954721dfaf0f94fe2003e ] Event timestamps are serialized using ctx->lock, make sure to hold it over reading all values. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 10cdb9c26b5d..4f1d4bfc607a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4433,6 +4433,8 @@ static int __perf_read_group_add(struct perf_event *leader, if (ret) return ret; + raw_spin_lock_irqsave(&ctx->lock, flags); + /* * Since we co-schedule groups, {enabled,running} times of siblings * will be identical to those of the leader, so we only publish one @@ -4455,8 +4457,6 @@ static int __perf_read_group_add(struct perf_event *leader, if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); - raw_spin_lock_irqsave(&ctx->lock, flags); - list_for_each_entry(sub, &leader->sibling_list, group_entry) { values[n++] += perf_event_count(sub); if (read_format & PERF_FORMAT_ID) -- 2.11.0