Re: [RESEND PATCH] cpufreq: unnecesary double free inpcc_cpufreq_do_osc

From: Dave Jones
Date: Thu Sep 30 2010 - 16:09:01 EST


On Thu, Sep 30, 2010 at 01:02:54PM -0700, David Rientjes wrote:
> > index 994230d..db7dc35 100644
> > --- a/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
> > +++ b/arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c
> > @@ -379,6 +379,8 @@ static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
> > if (!(supported & 0x1))
> > return -ENODEV;
> >
> > + return ret;
> > +
> > out_free:
> > kfree(output.pointer);
> > return ret;
>
> Why is the kfree() unnecessary? acpi_evaluate_object() will allocate a
> new output.pointer if it returns 0, so at this point in the code you would
> now be leaking the buffer.
>
> Instead, it would probably be better to fix the existing memory leaks in
> that function where we return -ENODEV without going to out_free when
> output.length is non-zero.

Oh, *duh*. That was subtle.
You, and Pekka are of course correct. I'll merge up Pekka's patch.

thanks,

Dave

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