Messages in this thread |  | | Subject | Re: [PATCH v3 2/3] perf: add arm64 smmuv3 pmu driver | From | Robin Murphy <> | Date | Wed, 3 Oct 2018 11:37:07 +0100 |
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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();
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