Re: [PATCH] intel_pstate: Use del_timer_sync in intel_pstate_cpu_stop

From: Srivatsa S. Bhat
Date: Mon Mar 24 2014 - 10:55:04 EST


On 03/24/2014 08:11 PM, dirk.brandewie@xxxxxxxxx wrote:
> From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
>
> Ensure that no timer callback is running since we are about to free
> the timer structure. We cannot guarantee that the call back is called
> on the CPU where the timer is running.
>
> Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Cc: cpufreq <cpufreq@xxxxxxxxxxxxxxx>

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

Regards,
Srivatsa S. Bhat

> ---
> drivers/cpufreq/intel_pstate.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index e9092fd..a4a9ba5 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -780,7 +780,7 @@ static int intel_pstate_cpu_stop(struct cpufreq_policy *policy)
>
> pr_info("intel_pstate CPU %d exiting\n", cpu_num);
>
> - del_timer(&all_cpu_data[cpu_num]->timer);
> + del_timer_sync(&all_cpu_data[cpu_num]->timer);
> intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
> kfree(all_cpu_data[cpu_num]);
> all_cpu_data[cpu_num] = NULL;
>

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