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 <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 4608af8aa53e7f3922ddee695d023b7bcd5cb35b Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@xxxxxxx>
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.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.2+
Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 3c29d36702a8..5426c04fe24b 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;
}