From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424558AbeE1LfO (ORCPT ); Mon, 28 May 2018 07:35:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:32854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424263AbeE1LNb (ORCPT ); Mon, 28 May 2018 07:13:31 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Vince Weaver , Ingo Molnar , Sasha Levin Subject: [PATCH 4.16 185/272] perf/core: Fix perf_output_read_group() Date: Mon, 28 May 2018 12:03:38 +0200 Message-Id: <20180528100256.188738427@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100240.256525891@linuxfoundation.org> References: <20180528100240.256525891@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra [ Upstream commit 9e5b127d6f33468143d90c8a45ca12410e4c3fa7 ] Mark reported his arm64 perf fuzzer runs sometimes splat like: armv8pmu_read_counter+0x1e8/0x2d8 armpmu_event_update+0x8c/0x188 armpmu_read+0xc/0x18 perf_output_read+0x550/0x11e8 perf_event_read_event+0x1d0/0x248 perf_event_exit_task+0x468/0xbb8 do_exit+0x690/0x1310 do_group_exit+0xd0/0x2b0 get_signal+0x2e8/0x17a8 do_signal+0x144/0x4f8 do_notify_resume+0x148/0x1e8 work_pending+0x8/0x14 which asserts that we only call pmu::read() on ACTIVE events. The above callchain does: perf_event_exit_task() perf_event_exit_task_context() task_ctx_sched_out() // INACTIVE perf_event_exit_event() perf_event_set_state(EXIT) // EXIT sync_child_event() perf_event_read_event() perf_output_read() perf_output_read_group() leader->pmu->read() Which results in doing a pmu::read() on an !ACTIVE event. I _think_ this is 'new' since we added attr.inherit_stat, which added the perf_event_read_event() to the exit path, without that perf_event_read_output() would only trigger from samples and for @event to trigger a sample, it's leader _must_ be ACTIVE too. Still, adding this check makes it consistent with the @sub case for the siblings. Reported-and-Tested-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5770,7 +5770,8 @@ static void perf_output_read_group(struc if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; - if (leader != event) + if ((leader != event) && + (leader->state == PERF_EVENT_STATE_ACTIVE)) leader->pmu->read(leader); values[n++] = perf_event_count(leader);