diff --git a/kernel/cpu.c b/kernel/cpu.c
index 2011ad8..da31165 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -149,7 +149,7 @@ int __cpuinit register_cpu_notifier(struct notifier_block *nb)
 
 EXPORT_SYMBOL(register_cpu_notifier);
 
-void unregister_cpu_notifier(struct notifier_block *nb)
+void __ref unregister_cpu_notifier(struct notifier_block *nb)
 {
 	cpu_maps_update_begin();
 	raw_notifier_chain_unregister(&cpu_chain, nb);