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

From: ethan zhao
Date: Sun Feb 01 2015 - 23:17:09 EST



On 2015/2/2 12:09, Viresh Kumar wrote:
On 2 February 2015 at 09:36, ethan zhao <ethan.zhao@xxxxxxxxxx> wrote:
Is that an idea it supposed to be or fact ?

if (!cpufreq_suspended)
cpufreq_policy_free(policy);

static void cpufreq_policy_free(struct cpufreq_policy *policy)
{
free_cpumask_var(policy->related_cpus);
free_cpumask_var(policy->cpus);
kfree(policy);
}

It seems
you just think about it ideally in mind.
We am talking about the policy allocation and de-allocation. right ?
I showed you the cpufreq_policy_free(policy) doesn't check kobject
refcount as above.

Hmmm, you are still sleeping in the kobject, wake up and don't mix
water anymore.

Thanks,
Ethan


if (!cpufreq_suspended)
cpufreq_policy_put_kobj(policy);

static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
{
...

kobject_put(kobj);

/*
* We need to make sure that the underlying kobj is
* actually not referenced anymore by anybody before we
* proceed with unloading.
*/
pr_debug("waiting for dropping of refcount\n");
wait_for_completion(cmp);
}

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