Commit 4608af8a authored Oct 03, 2017 by Marc Zyngier Committed by Pawel Moll Dec 04, 2017

bus: arm-cci: Fix use of smp_processor_id() in preemptible context



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 <marc.zyngier@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org # 4.2+
Signed-off-by: Pawel Moll <pawel.moll@arm.com>

parent b18c2b94

drivers/bus/arm-cci.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}