[PATCH 10/11] hwmon: (pmbus) Release devres allocated memory after devm_thermal_of_zone_register error

[Guenter Roeck <linux@roeck-us.net>]

In pmbus_thermal_add_sensor(), a devres memory leak occurs when a PMBus
temperature sensor is initialized but no thermal zone is configured for
it.
The function allocates a pmbus_thermal_data structure using
devm_kzalloc(). It then attempts to register the sensor with the thermal
subsystem via devm_thermal_of_zone_register(). If this registration
returns -ENODEV (e.g., when no thermal zone is mapped in the Device Tree
or CONFIG_THERMAL_OF is disabled), the function intentionally catches the
error and returns 0 to allow device probing to continue.

Because devm_kfree() is not called on the -ENODEV path, the unused tdata
structure remains allocated on the device's managed resource list. Since
most PMBus temperature sensors are not attached to thermal zones, this
results in an accumulation of unused objects that needlessly consume kernel
memory for the lifetime of the PMBus device.

Add the missing call to devm_kfree() to fix the problem.

Fixes: 3aa74796cfd0 ("hwmon: (pmbus) Register with thermal for PSC_TEMPERATURE")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/pmbus/pmbus_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 9bccbf41c884..574d9879bdcf 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -1535,8 +1535,10 @@ static int pmbus_thermal_add_sensor(struct pmbus_data *pmbus_data,
 	 * If CONFIG_THERMAL_OF is disabled, this returns -ENODEV,
 	 * so ignore that error but forward any other error.
 	 */
-	if (IS_ERR(tzd) && (PTR_ERR(tzd) != -ENODEV))
+	if (IS_ERR(tzd) && (PTR_ERR(tzd) != -ENODEV)) {
+		devm_kfree(dev, tdata);
 		return PTR_ERR(tzd);
+	}
 
 	return 0;
 }
-- 
2.45.2