[PATCH 05/13] intel_idle: Fix deallocation order on the driver exit path.

Len Brown
2016-04-06T21:01:49Z

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>
---
drivers/idle/intel_idle.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index c50859d..5b309e5 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -1379,16 +1379,16 @@ 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);
--
2.8.0.rc4.16.g56331f8