From patchwork Wed Oct 17 15:33:42 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 1606681 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 5432CDFABE for ; Wed, 17 Oct 2012 15:37:57 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TOVeV-0004L2-6N; Wed, 17 Oct 2012 15:35:24 +0000 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TOVd4-0003Ox-2q for linux-arm-kernel@lists.infradead.org; Wed, 17 Oct 2012 15:33:57 +0000 Received: from mudshark.cambridge.arm.com (mudshark.cambridge.arm.com [10.1.79.58]) by cam-admin0.cambridge.arm.com (8.12.6/8.12.6) with ESMTP id q9HFXpE7019603; Wed, 17 Oct 2012 16:33:51 +0100 (BST) Received: by mudshark.cambridge.arm.com (Postfix, from userid 1000) id 2E01CC2A93; Wed, 17 Oct 2012 16:33:47 +0100 (BST) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 5/7] ARM: perf: register cpu_notifier at driver init Date: Wed, 17 Oct 2012 16:33:42 +0100 Message-Id: <1350488024-3224-6-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1350488024-3224-1-git-send-email-will.deacon@arm.com> References: <1350488024-3224-1-git-send-email-will.deacon@arm.com> X-Spam-Note: CRM114 invocation failed X-Spam-Score: -7.3 (-------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-7.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.96.50 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Mark Rutland , Will Deacon X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Mark Rutland The current practice of registering the cpu hotplug notifier at PMU registration time won't be safe with multiple PMUs, as we'll repeatedly attempt to register the notifier. This has the unfortunate effect of silently corrupting the notifier list, leading to boot stalling. Instead, register the notifier at init time. Its sanity checks will prevent anything bad from happening if the notifier is called before we have any PMUs registered. Signed-off-by: Mark Rutland Signed-off-by: Will Deacon --- arch/arm/kernel/perf_event_cpu.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c index 02244fa..71c824c 100644 --- a/arch/arm/kernel/perf_event_cpu.c +++ b/arch/arm/kernel/perf_event_cpu.c @@ -285,7 +285,6 @@ static int __devinit cpu_pmu_device_probe(struct platform_device *pdev) cpu_pmu = pmu; cpu_pmu->plat_device = pdev; cpu_pmu_init(cpu_pmu); - register_cpu_notifier(&cpu_pmu_hotplug_notifier); armpmu_register(cpu_pmu, cpu_pmu->name, PERF_TYPE_RAW); return 0; @@ -303,6 +302,16 @@ static struct platform_driver cpu_pmu_driver = { static int __init register_pmu_driver(void) { - return platform_driver_register(&cpu_pmu_driver); + int err; + + err = register_cpu_notifier(&cpu_pmu_hotplug_notifier); + if (err) + return err; + + err = platform_driver_register(&cpu_pmu_driver); + if (err) + unregister_cpu_notifier(&cpu_pmu_hotplug_notifier); + + return err; } device_initcall(register_pmu_driver);