The code is racy and the check with cpuidle_curr_driver should be
done under the lock.
I don't find a path in the different drivers where that could happen
because the arch specific drivers are written in such way it is not
possible to register a driver while it is unregistered, except maybe
in a very improbable case when "intel_idle" and "processor_idle" are
competing. One could unregister a driver, while the other one is
registering.
Signed-off-by: Daniel Lezcano <daniel.lezc...@linaro.org>
Acked-by: Peter De Schrijver <pdeschrij...@nvidia.com>
---
drivers/cpuidle/driver.c | 10 +---------
1 files changed, 1 insertions(+), 9 deletions(-)
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 39ba8e1..3e59075 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -85,17 +85,9 @@ EXPORT_SYMBOL_GPL(cpuidle_get_driver);
*/
void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
- if (drv != cpuidle_curr_driver) {
- WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
- drv->name);
- return;
- }
-
spin_lock(&cpuidle_driver_lock);
-
- if (!WARN_ON(drv->refcnt > 0))
+ if (drv == cpuidle_curr_driver && !WARN_ON(drv->refcnt > 0))
cpuidle_curr_driver = NULL;
-
spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
--
1.7.5.4
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