Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755515AbdLGNb5 (ORCPT ); Thu, 7 Dec 2017 08:31:57 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34238 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755395AbdLGNLK (ORCPT ); Thu, 7 Dec 2017 08:11:10 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Linus Torvalds , Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH 4.14 31/75] perf/core: Fix __perf_read_group_add() locking Date: Thu, 7 Dec 2017 14:07:53 +0100 Message-Id: <20171207130820.020591977@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171207130818.742746317@linuxfoundation.org> References: <20171207130818.742746317@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 44 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4433,6 +4433,8 @@ static int __perf_read_group_add(struct 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 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)