Re: od_set_powersave_bias: NULL pointer dereference

From: Viresh Kumar
Date: Wed Jun 26 2013 - 10:32:36 EST


On 26 June 2013 19:58, Jacob Shin <jacob.shin@xxxxxxx> wrote:
> On Wed, Jun 26, 2013 at 12:18:27PM +0530, Viresh Kumar wrote:

>> I am not sure if this is enough. What if we had ondemand as the
>> governor initially, then we changed it to something else. Now also
>> cur_policy contains a address and isn't zero.
>
> Right, so we check below ..
>
>>
>> > cpumask_or(&done, &done, policy->cpus);
>> > +
>> > + if (policy->governor != &cpufreq_gov_ondemand)
>> > + continue;
>
> This should catch that case no ?

Policy might be freed and reallocated by then. And so doing
policy->governor is dangerous.
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