Re: [PATCH Resend] cpufreq: Set cpufreq_cpu_data to NULL before putting kobject

On 2 February 2015 at 08:50, ethan zhao ethan.zhao@oracle.com wrote:

This seems couldn't prevent all the 'bad thing' from happening, E.G.

Thread A: Workqueue: kacpi_notify

acpi_processor_notify() acpi_processor_ppc_has_changed() cpufreq_update_policy() cpufreq_cpu_get()

We take cpufreq_driver_lock() here, and so this will block thread B.

       beginning the deference of policy        Thread B:
       ... ... __cpufreq_remove_dev_finish()

cpufreq_policy_free(policy);

Perhaps move policy->rwsem out side the policy structure is a way to avoid it completely. and you could stopping the PPC thread stepping forward as my patch as temporary workaround.

I couldn't understand your problem completely. Apart from giving a detailed look of what's going on both threads, always specify where the BUG actually is..