On Thu, May 14, 2015 at 12:04:28PM +0100, Mark Rutland wrote: > On Thu, May 14, 2015 at 11:50:24AM +0100, Pawel Moll wrote: > > When migrating events the driver picks another cpu using > > cpumask_any_but() function, which returns value >= nr_cpu_ids > > when there is none available, not a negative value as the code > > assumed. Fixed now. > > The fix looks good to me: > > Acked-by: Mark Rutland <mark.rutland@xxxxxxx> > > Does this need to be CC'd to stable? What does perf_pmu_migrate_context > do when passed a target >= nr_cpus? Never mind, it looks like we can never encounter that case anyway. In the case of kexec or reset we won't notify CPU_DOWN_PREPARE on the final CPU, and we can't hotplug the final CPU. Which means that the target check is irrelevant as we should always get a valid cpu back from cpumask_any_but in the cases we'll call it. So we could just delete it entirely, assuming I haven't missed a CPU_DOWN_PREPARE notification path... Mark. > > diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c > > index 7d9879e..cc322fb 100644 > > --- a/drivers/bus/arm-ccn.c > > +++ b/drivers/bus/arm-ccn.c > > @@ -1184,7 +1184,7 @@ static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb, > > if (!cpumask_test_and_clear_cpu(cpu, &dt->cpu)) > > break; > > target = cpumask_any_but(cpu_online_mask, cpu); > > - if (target < 0) > > + if (target >= nr_cpu_ids) > > break; > > perf_pmu_migrate_context(&dt->pmu, cpu, target); > > cpumask_set_cpu(target, &dt->cpu); > > -- > > 2.1.0 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
