__cpufreq_governor() must be called with a correct policy->cpus mask. In __cpufreq_remove_dev() we initially clear policy->cpus with cpumask_clear_cpu() and then call __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT). If the governor is doing some per-cpu stuff in EXIT callback, this can create uncertain behavior.
Generic governors in drivers/cpufreq/ doesn't do any per-cpu stuff in EXIT callback and so we don't face any issues currently. But its better to keep the code clean, so we don't face any issues in future.
Now, we call cpumask_clear_cpu() only when multiple cpus are managed by policy.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com --- drivers/cpufreq/cpufreq.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 85963fc..0072b46 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1036,7 +1036,9 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif
WARN_ON(lock_policy_rwsem_write(cpu)); cpus = cpumask_weight(data->cpus); - cpumask_clear_cpu(cpu, data->cpus); + + if (cpus > 1) + cpumask_clear_cpu(cpu, data->cpus); unlock_policy_rwsem_write(cpu);
if (cpu != data->cpu) {