[PATCH 2/9] thermal/core: Delete device under thermal device zone lock

[Guenter Roeck]

Thermal device attributes may still be opened after unregistering
the thermal zone and deleting the thermal device.

Currently there is no protection against accessing thermal device
operations after unregistering a thermal zone. To enable adding
such protection, protect the device delete operation with the
thermal zone device mutex. This requires splitting the call to
device_unregister() into its components, device_del() and put_device().
Only the first call can be executed under mutex protection, since
put_device() may result in releasing the thermal zone device memory.

Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
 drivers/thermal/thermal_core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index f548875a016d..562ece8d16aa 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1391,7 +1391,12 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz)
 	thermal_remove_hwmon_sysfs(tz);
 	ida_free(&thermal_tz_ida, tz->id);
 	ida_destroy(&tz->ida);
-	device_unregister(&tz->device);
+
+	mutex_lock(&tz->lock);
+	device_del(&tz->device);
+	mutex_unlock(&tz->lock);
+
+	put_device(&tz->device);
 
 	thermal_notify_tz_delete(tz_id);
 }
-- 
2.36.2