--- x/drivers/base/class.c
+++ y/drivers/base/class.c
@@ -61,6 +61,7 @@ static void class_release(struct kobject
 		pr_debug("class '%s' does not have a release() function, "
 			 "be careful\n", class->name);
 
+	lockdep_unregister_key(&cp->lock_key);
 	kfree(cp);
 }
 
@@ -173,6 +174,7 @@ int class_register(struct class *cls)
 	__mutex_init(&cp->mutex, "subsys mutex", key);
 	error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
 	if (error) {
+		lockdep_unregister_key(key);
 		kfree(cp);
 		return error;
 	}
@@ -200,6 +202,7 @@ int class_register(struct class *cls)
 	return 0;
 
 err_out:
+	lockdep_unregister_key(key);
 	kfree(cp);
 	cls->p = NULL;
 	return error;