intel_idle: Fix deallocation order on the driver exit path.

In the module_exit() method, this driver first frees its per-CPU
pointer, then unregisters a callback making use of the pointer.
Furthermore, the function, intel_idle_cpuidle_devices_uninit, is racy
against CPU hot plugging as it calls for_each_online_cpu().

This patch corrects the issues by unregistering first on the exit path
while holding the hot plug lock.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index cb85c4c42ff92dce2bd5587552ab635b8dc4625d..4a1de3dcbf8596dadd9eaf764c819bd6ae318d2d 100644 (file)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -1242,16 +1242,16 @@ static int __init intel_idle_init(void)
 
 static void __exit intel_idle_exit(void)
 {
-       intel_idle_cpuidle_devices_uninit();
-       cpuidle_unregister_driver(&intel_idle_driver);
-
        cpu_notifier_register_begin();
 
        if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
                on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
        __unregister_cpu_notifier(&cpu_hotplug_notifier);
+       intel_idle_cpuidle_devices_uninit();
 
        cpu_notifier_register_done();
+
+       cpuidle_unregister_driver(&intel_idle_driver);
 }
 
 module_init(intel_idle_init);