linux-kernel - [PATCH] thermal/core/power_allocator: avoid cdev->state can not be reset

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 9 Mar 2023 21:55:15 +0800
From:   Di Shen <di.shen@...soc.com>
To:     <lukasz.luba@....com>, <rafael@...nel.org>
CC:     <daniel.lezcano@...aro.org>, <amitk@...nel.org>,
        <rui.zhang@...el.com>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <xuewen.yan@...soc.com>
Subject: [PATCH] thermal/core/power_allocator: avoid cdev->state can not be reset

Commit 0952177f2a1f (thermal/core/power_allocator: Update once cooling devices when temp is low)
add a update flag to update cooling device only once when temp is low.
But when the switch_on_temp is set to be a higher value, the cooling device state
may not be reset to max, because the last_temp is smaller than the switch_on_temp.

For example:
First:
swicth_on_temp=70 control_temp=85;

Then userspace change the trip_temp:
swicth_on_temp=45 control_temp=55 cur_temp=54

Then userspace reset the trip_temp:
swicth_on_temp=70 control_temp=85 cur_temp=57 last_temp=54

At this time, the cooling device state should be reset to be max.
However, because cur_temp(57) < switch_on_temp(70)
last_temp(54) < swicth_on_temp(70) --> update = false
When update is false, the cooling device state can not be reset.

So delete the update condition, so that the cooling device state
could be reset.

Fixes: 0952177f2a1f (thermal/core/power_allocator: Update once cooling devices when temp is low)
Signed-off-by: Di Shen <di.shen@...soc.com>
---
 drivers/thermal/gov_power_allocator.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
index 0eaf1527d3e3..153bf528b98c 100644
--- a/drivers/thermal/gov_power_allocator.c
+++ b/drivers/thermal/gov_power_allocator.c
@@ -560,7 +560,7 @@ static void reset_pid_controller(struct power_allocator_params *params)
 	params->prev_err = 0;
 }
 
-static void allow_maximum_power(struct thermal_zone_device *tz, bool update)
+static void allow_maximum_power(struct thermal_zone_device *tz)
 {
 	struct thermal_instance *instance;
 	struct power_allocator_params *params = tz->governor_data;
@@ -582,8 +582,7 @@ static void allow_maximum_power(struct thermal_zone_device *tz, bool update)
 		 */
 		cdev->ops->get_requested_power(cdev, &req_power);
 
-		if (update)
-			__thermal_cdev_update(instance->cdev);
+		__thermal_cdev_update(instance->cdev);
 
 		mutex_unlock(&instance->cdev->lock);
 	}
@@ -697,7 +696,6 @@ static int power_allocator_throttle(struct thermal_zone_device *tz, int trip_id)
 	struct power_allocator_params *params = tz->governor_data;
 	struct thermal_trip trip;
 	int ret;
-	bool update;
 
 	lockdep_assert_held(&tz->lock);
 
@@ -710,10 +708,9 @@ static int power_allocator_throttle(struct thermal_zone_device *tz, int trip_id)
 
 	ret = __thermal_zone_get_trip(tz, params->trip_switch_on, &trip);
 	if (!ret && (tz->temperature < trip.temperature)) {
-		update = (tz->last_temperature >= trip.temperature);
 		tz->passive = 0;
 		reset_pid_controller(params);
-		allow_maximum_power(tz, update);
+		allow_maximum_power(tz);
 		return 0;
 	}
 
-- 
2.17.1