diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 6aa46a90ff028691f97627765f593d864bc885a1..3796434991faa83466c85c8779a072db1278ef33 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -128,11 +128,12 @@ EXPORT_SYMBOL_GPL(watchdog_register_device);
 void watchdog_unregister_device(struct watchdog_device *wdd)
 {
 	int ret;
-	int devno = wdd->cdev.dev;
+	int devno;
 
 	if (wdd == NULL)
 		return;
 
+	devno = wdd->cdev.dev;
 	ret = watchdog_dev_unregister(wdd);
 	if (ret)
 		pr_err("error unregistering /dev/watchdog (err=%d)\n", ret);