The helper function, intel_idle_cpuidle_devices_uninit, frees the globally allocated per-CPU data. However, this function is invoked from the hot plug notifier callback at a time when freeing that data is not safe.
If the call to cpuidle_register_driver() should fail (say, due to lack of memory), then the driver will free its per-CPU region. On the *next* CPU_ONLINE event, the driver will happily use the region again and even free it again if the failure repeats. This patch fixes the issue by moving the call to free_percpu() outside of the helper function at the two call sites that actually need to free the per-CPU data. Cc: Len Brown <[email protected]> Cc: [email protected] Signed-off-by: Richard Cochran <[email protected]> --- drivers/idle/intel_idle.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 5dd741f..0b56872 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1002,7 +1002,7 @@ static int __init intel_idle_probe(void) /* * intel_idle_cpuidle_devices_uninit() - * unregister, free cpuidle_devices + * Unregisters the cpuidle devices. */ static void intel_idle_cpuidle_devices_uninit(void) { @@ -1013,9 +1013,6 @@ static void intel_idle_cpuidle_devices_uninit(void) dev = per_cpu_ptr(intel_idle_cpuidle_devices, i); cpuidle_unregister_device(dev); } - - free_percpu(intel_idle_cpuidle_devices); - return; } /* @@ -1231,6 +1228,7 @@ static int __init intel_idle_init(void) if (retval) { cpu_notifier_register_done(); cpuidle_unregister_driver(&intel_idle_driver); + free_percpu(intel_idle_cpuidle_devices); return retval; } } @@ -1253,6 +1251,7 @@ static void __exit intel_idle_exit(void) cpu_notifier_register_done(); cpuidle_unregister_driver(&intel_idle_driver); + free_percpu(intel_idle_cpuidle_devices); } module_init(intel_idle_init); -- 2.1.4
