FAILED: patch "[PATCH] bus: arm-cci: Fix use of smp_processor_id() in preemptible" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Marc Zyngier <[email protected]>
Date: Tue, 3 Oct 2017 18:14:13 +0100
Subject: [PATCH] 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.

index 3c29d36702a8..5426c04fe24b 100644
@@ -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;
 }