diff --git a/[refs] b/[refs]
index f36f82ae4d63..3d4150247e22 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 209efae12981f3d2d694499b761def10895c078c
+refs/heads/master: 6e32d479db6079dd5d4309aa66aecbcf2664a5fe
diff --git a/trunk/kernel/cpu.c b/trunk/kernel/cpu.c
index 42bd331ee0ab..a2491a2d62bb 100644
--- a/trunk/kernel/cpu.c
+++ b/trunk/kernel/cpu.c
@@ -601,6 +601,11 @@ cpu_hotplug_pm_callback(struct notifier_block *nb,
 
 static int __init cpu_hotplug_pm_sync_init(void)
 {
+	/*
+	 * cpu_hotplug_pm_callback has higher priority than x86
+	 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
+	 * to disable cpu hotplug to avoid cpu hotplug race.
+	 */
 	pm_notifier(cpu_hotplug_pm_callback, 0);
 	return 0;
 }