iwlwifi: fix kernel crash when unregistering thermal zone

A recent firmware change seems to have enabled thermal zones on the
iwlwifi driver. Unfortunately, my device fails when registering the
thermal zone. This doesn't stop the driver from attempting to unregister
the thermal zone at unload time, triggering a NULL pointer deference in
strlen() off the thermal_zone_device_unregister() path.

Don't unregister if name is NULL, for that case we failed registering.
Do the same for the cooling zone.

Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
index 63a051be832ed44b30978b4d031464b15765df20..bec7d9c46087d3c8fed48d5858f4f116797eceed 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tt.c
@@ -843,8 +843,10 @@ static void iwl_mvm_thermal_zone_unregister(struct iwl_mvm *mvm)
                return;
 
        IWL_DEBUG_TEMP(mvm, "Thermal zone device unregister\n");
-       thermal_zone_device_unregister(mvm->tz_device.tzone);
-       mvm->tz_device.tzone = NULL;
+       if (mvm->tz_device.tzone) {
+               thermal_zone_device_unregister(mvm->tz_device.tzone);
+               mvm->tz_device.tzone = NULL;
+       }
 }
 
 static void iwl_mvm_cooling_device_unregister(struct iwl_mvm *mvm)
@@ -853,8 +855,10 @@ static void iwl_mvm_cooling_device_unregister(struct iwl_mvm *mvm)
                return;
 
        IWL_DEBUG_TEMP(mvm, "Cooling device unregister\n");
-       thermal_cooling_device_unregister(mvm->cooling_dev.cdev);
-       mvm->cooling_dev.cdev = NULL;
+       if (mvm->cooling_dev.cdev) {
+               thermal_cooling_device_unregister(mvm->cooling_dev.cdev);
+               mvm->cooling_dev.cdev = NULL;
+       }
 }
 #endif /* CONFIG_THERMAL */