From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751418AbdJCROt (ORCPT ); Tue, 3 Oct 2017 13:14:49 -0400 Received: from foss.arm.com ([217.140.101.70]:51950 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072AbdJCROr (ORCPT ); Tue, 3 Oct 2017 13:14:47 -0400 From: Marc Zyngier To: Lorenzo Pieralisi , Suzuki K Poulose , Pawel Moll , Mark Rutland Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] bus: arm-cci: Fix use of smp_processor_id() in preemptible context Date: Tue, 3 Oct 2017 18:14:13 +0100 Message-Id: <20171003171413.18592-3-marc.zyngier@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171003171413.18592-1-marc.zyngier@arm.com> References: <20171003171413.18592-1-marc.zyngier@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ARM CCI driver seem to be using smp_processor_id() in a preemptible context, which is likely to make a DEBUG_PREMPT kernel scream at boot time. Turn this into a get_cpu()/put_cpu() that extends over the CPU hotplug registration, making sure that we don't race against a CPU down operation. Signed-off-by: Marc Zyngier --- drivers/bus/arm-cci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c index c49da15d9790..d1aa11c083f9 100644 --- a/drivers/bus/arm-cci.c +++ b/drivers/bus/arm-cci.c @@ -1755,14 +1755,17 @@ static int cci_pmu_probe(struct platform_device *pdev) raw_spin_lock_init(&cci_pmu->hw_events.pmu_lock); mutex_init(&cci_pmu->reserve_mutex); atomic_set(&cci_pmu->active_events, 0); - cpumask_set_cpu(smp_processor_id(), &cci_pmu->cpus); + cpumask_set_cpu(get_cpu(), &cci_pmu->cpus); ret = cci_pmu_init(cci_pmu, pdev); - if (ret) + if (ret) { + put_cpu(); return ret; + } cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CCI_ONLINE, &cci_pmu->node); + put_cpu(); pr_info("ARM %s PMU driver probed", cci_pmu->model->name); return 0; } -- 2.11.0