Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf

From: Rafael J. Wysocki
Date: Wed Sep 14 2016 - 20:44:10 EST


On Wednesday, September 14, 2016 04:08:28 PM Hoan Tran wrote:
> This patch fixes overflow issue when calculating the desired_perf.
>
> Signed-off-by: Hoan Tran <hotran@xxxxxxx>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 894e465..3e0961e 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -84,7 +84,8 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>
> cpu = all_cpu_data[policy->cpu];
>
> - cpu->perf_ctrls.desired_perf = target_freq * policy->max / cppc_dmi_max_khz;
> + cpu->perf_ctrls.desired_perf =
> + (u64)target_freq * policy->max / cppc_dmi_max_khz;
> freqs.old = policy->cur;
> freqs.new = target_freq;

That's on top of the CPPC material in linux-next I gather?

Which commit does it fix?

Thanks,
Rafael