On 21/09/18 16:08, Shameer Kolothum wrote:
[...]
+
+ err = cpuhp_state_add_instance_nocalls(cpuhp_state_num,
+ &smmu_pmu->node);
In theory a hotplug event could happen as soon as the instance is
registered...
+ if (err) {
+ dev_err(dev, "Error %d registering hotplug, PMU @%pa\n",
+ err, &res_0->start);
+ return err;
+ }
+
+ /* Pick one CPU to be the preferred one to use */
+ smmu_pmu->on_cpu = get_cpu();
...so this looks too late, i.e. a race here can result in a bogus call
to perf_pmu_migrate_context() with an uninitialised pmu.
Robin.
+ WARN_ON(irq_set_affinity(smmu_pmu->irq, cpumask_of(smmu_pmu->on_cpu)));
+
+ err = perf_pmu_register(&smmu_pmu->pmu, name, -1);
+ if (err) {
+ dev_err(dev, "Error %d registering PMU @%pa\n",
+ err, &res_0->start);
+ goto out_unregister;
+ }
+
+ put_cpu();
