1 files changed, 10 insertions, 3 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 42bd331ee0ab..3046a503242c 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -348,11 +348,13 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
         unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
         struct task_struct *idle;
 
-        if (cpu_online(cpu) || !cpu_present(cpu))
-                return -EINVAL;
-
         cpu_hotplug_begin();
 
+        if (cpu_online(cpu) || !cpu_present(cpu)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
         idle = idle_thread_get(cpu);
         if (IS_ERR(idle)) {
                 ret = PTR_ERR(idle);
@@ -601,6 +603,11 @@ 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;
 }