From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753932AbcHRKxJ (ORCPT ); Thu, 18 Aug 2016 06:53:09 -0400 Received: from terminus.zytor.com ([198.137.202.10]:57842 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753861AbcHRKxH (ORCPT ); Thu, 18 Aug 2016 06:53:07 -0400 Date: Thu, 18 Aug 2016 03:52:34 -0700 From: tip-bot for David Carrillo-Cisneros Message-ID: Cc: davidcc@google.com, mingo@kernel.org, vincent.weaver@maine.edu, eranian@google.com, tglx@linutronix.de, alexander.shishkin@linux.intel.com, linux-kernel@vger.kernel.org, jolsa@redhat.com, torvalds@linux-foundation.org, vegard.nossum@gmail.com, kan.liang@intel.com, pjt@google.com, acme@redhat.com, peterz@infradead.org, hpa@zytor.com Reply-To: tglx@linutronix.de, eranian@google.com, vincent.weaver@maine.edu, mingo@kernel.org, davidcc@google.com, peterz@infradead.org, hpa@zytor.com, kan.liang@intel.com, acme@redhat.com, pjt@google.com, vegard.nossum@gmail.com, torvalds@linux-foundation.org, jolsa@redhat.com, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com In-Reply-To: <1471467307-61171-2-git-send-email-davidcc@google.com> References: <1471467307-61171-2-git-send-email-davidcc@google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf/core: Check return value of the perf_event_read() IPI Git-Commit-ID: 71e7bc2bab77e64882c031c2af943c3256c1adb0 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 71e7bc2bab77e64882c031c2af943c3256c1adb0 Gitweb: http://git.kernel.org/tip/71e7bc2bab77e64882c031c2af943c3256c1adb0 Author: David Carrillo-Cisneros AuthorDate: Wed, 17 Aug 2016 13:55:04 -0700 Committer: Ingo Molnar CommitDate: Thu, 18 Aug 2016 10:35:52 +0200 perf/core: Check return value of the perf_event_read() IPI The call to smp_call_function_single in perf_event_read() may fail if an invalid or not online CPU index is passed. Warn user if such bug is present and return error. Signed-off-by: David Carrillo-Cisneros Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Paul Turner Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vegard Nossum Cc: Vince Weaver Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index a5fc5c8..5650f53 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3549,9 +3549,10 @@ static int perf_event_read(struct perf_event *event, bool group) .group = group, .ret = 0, }; - smp_call_function_single(event->oncpu, - __perf_event_read, &data, 1); - ret = data.ret; + ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1); + /* The event must have been read from an online CPU: */ + WARN_ON_ONCE(ret); + ret = ret ? : data.ret; } else if (event->state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags;