4.9-stable review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier marc.zyngier@arm.com
commit 4608af8aa53e7f3922ddee695d023b7bcd5cb35b upstream.
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 Signed-off-by: Pawel Moll pawel.moll@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/bus/arm-cci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/bus/arm-cci.c +++ b/drivers/bus/arm-cci.c @@ -1755,14 +1755,17 @@ static int cci_pmu_probe(struct platform 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; }