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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E63B0C433EF for ; Mon, 11 Apr 2022 10:04:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345023AbiDKKHA (ORCPT ); Mon, 11 Apr 2022 06:07:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345013AbiDKKGt (ORCPT ); Mon, 11 Apr 2022 06:06:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F37CDAE74 for ; Mon, 11 Apr 2022 03:04:34 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6B4A1169E; Mon, 11 Apr 2022 03:04:34 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.9.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6CC9A3F5A1; Mon, 11 Apr 2022 03:04:33 -0700 (PDT) Date: Mon, 11 Apr 2022 11:04:26 +0100 From: Mark Rutland To: Rob Herring Cc: Will Deacon , Al Grant , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm_pmu: Validate single/group leader events Message-ID: References: <20220408203330.4014015-1-robh@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220408203330.4014015-1-robh@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rob, On Fri, Apr 08, 2022 at 03:33:30PM -0500, Rob Herring wrote: > In the case where there is only a cycle counter available (i.e. > PMCR_EL0.N is 0) and an event other than CPU cycles is opened, the open > should fail as the event can never possibly be scheduled. However, the > event validation when an event is opened is skipped when the group > leader is opened. Fix this by always validating the group leader events. > > Reported-by: Al Grant > Cc: Will Deacon > Cc: Mark Rutland > Signed-off-by: Rob Herring This looks obviously correct to me, so FWIW: Acked-by: Mark Rutland Just to check, have you tested this (e.g. by running on a platform with PMCR_EL0.N == 0, or hacking the PMU probing to report just the cycle counter) Thanks, Mark. > --- > drivers/perf/arm_pmu.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 9694370651fa..59d3980b8ca2 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -400,6 +400,9 @@ validate_group(struct perf_event *event) > if (!validate_event(event->pmu, &fake_pmu, leader)) > return -EINVAL; > > + if (event == leader) > + return 0; > + > for_each_sibling_event(sibling, leader) { > if (!validate_event(event->pmu, &fake_pmu, sibling)) > return -EINVAL; > @@ -489,12 +492,7 @@ __hw_perf_event_init(struct perf_event *event) > local64_set(&hwc->period_left, hwc->sample_period); > } > > - if (event->group_leader != event) { > - if (validate_group(event) != 0) > - return -EINVAL; > - } > - > - return 0; > + return validate_group(event); > } > > static int armpmu_event_init(struct perf_event *event) > -- > 2.32.0 >