From 879c9dc511732b74a04f11336e00f12783337a8a Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Wed, 20 Dec 2023 23:17:51 +0000 Subject: thermal/sysfs: Update instance->weight under tz lock User space can change the weight of a thermal instance via sysfs while the .throttle() callback is running for a governor, because weight_store() does not use the zone lock. The IPA governor uses instance weight values for power calculations and caches the sum of them as total_weight, so it gets confused when one of them changes while its .throttle() callback is running. To prevent that from happening, use thermal zone locking in weight_store(). Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki --- drivers/thermal/thermal_sysfs.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/thermal/thermal_sysfs.c') diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index d8ff74a4338a..299c0fb16593 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -936,7 +936,11 @@ ssize_t weight_store(struct device *dev, struct device_attribute *attr, return ret; instance = container_of(attr, struct thermal_instance, weight_attr); + + /* Don't race with governors using the 'weight' value */ + mutex_lock(&instance->tz->lock); instance->weight = weight; + mutex_unlock(&instance->tz->lock); return count; } -- cgit v1.2.3