On Thursday 13 April 2017 10:36 AM, Eduardo Valentin wrote:
> Hey,
>
> On Wed, Apr 12, 2017 at 02:42:12PM +0530, Keerthy wrote:
>> thermal_zone_device_check --> thermal_zone_device_update -->
>> handle_thermal_trip --> handle_critical_trips --> orderly_poweroff
>>
>> The above sequence happens every 250/500 mS based on the configuration.
>> The orderly_poweroff function is getting called every 250/500 mS.
>> With a full fledged file system it takes at least 5-10 Seconds to
>> power off gracefully.
>>
>> In that period due to the thermal_zone_device_check triggering
>> periodically the thermal work queues bombard with
>> orderly_poweroff calls multiple times eventually leading to
>> failures in gracefully powering off the system.
>>
>> Make sure that orderly_poweroff is called only once.
>>
>> Fixes: 0c01ebbfd3caf1d ("Thermal: Remove throttling logic out of thermal_sys.c")
>
> Why? how the above commit introduced this issue?
git blame showed me that. I can remove this. Let me know if you have the
right commit that introduced this.
>
>> Reported-by: Nishanth Menon <nm@xxxxxx>
>> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
>> ---
>> drivers/thermal/thermal_core.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
>> index 11f0675..4e68ce0 100644
>> --- a/drivers/thermal/thermal_core.c
>> +++ b/drivers/thermal/thermal_core.c
>> @@ -326,6 +326,7 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
>> int trip, enum thermal_trip_type trip_type)
>> {
>> int trip_temp;
>> + static bool power_off_triggered;
>>
>
> I am not convinced this change does what you say it does..
>
>> tz->ops->get_trip_temp(tz, trip, &trip_temp);
>>
>> @@ -338,11 +339,12 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
>> if (tz->ops->notify)
>> tz->ops->notify(tz, trip, trip_type);
>>
>> - if (trip_type == THERMAL_TRIP_CRITICAL) {
>> + if (trip_type == THERMAL_TRIP_CRITICAL && !power_off_triggered) {
>> dev_emerg(&tz->device,
>> "critical temperature reached(%d C),shutting down\n",
>> tz->temperature / 1000);
>> orderly_poweroff(true);
>
> Imagine you have two zones about to enter critical path. thermal zone 0
> first gets into critical, and at this line (btween orderly_poweroff()
> and you set your flag), it gets preempted. Then thermal zone 1 also
> enters the critical path, then happens to be scheduled, you essentially
> end up still calling orderly_poweroff() twice, which is what this patch
> is supposed to avoid.
>
> You better simply use a lock to serialize code execution.
Okay understood. Will do it in the next version.
>
> BR,
>
>> + power_off_triggered = true;
>> }
>> }
>>
>> --
>> 1.9.1
>>
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