Re: [PATCH 3/3] cpufreq: Don't use cpu removed during cpufreq_driver_unregister

From: Viresh Kumar
Date: Fri Jan 04 2013 - 00:19:00 EST

On 3 January 2013 19:55, Srivatsa S. Bhat
<srivatsa.bhat@xxxxxxxxxxxxxxxxxx> wrote:
> I took a quick look at the problem you described above, and the cpufreq code..
> If we cannot avoid calling cpufreq_add_dev() from cpufreq_remove_dev(), then I can't
> think of anything better than what your patch does.

Good :)

> BTW, off-topic, while going through that path, I think I found a memory leak
> in __cpufreq_remove_dev():
> if (unlikely(cpumask_weight(data->cpus) > 1)) {
> for_each_cpu(j, data->cpus) {
> if (j == cpu)
> continue;
> per_cpu(cpufreq_cpu_data, j) = NULL;
> }
> }
> We are assigning NULL without freeing that memory.

Not really. All cpus in affected_cpus (data->cpus), share the same
policy structure.
We have already taken backup of cpufreq_cpu_data for the first cpu in "data" and
are freeing it here:

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