cpuidle: add cpuidle_unregister_driver() error check

Assure that cpuidle_unregister_driver() will not clobber
the registered driver if unregistered by somebody else.

Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 2257004..826b5c0 100644 (file)
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -45,8 +45,11 @@ EXPORT_SYMBOL_GPL(cpuidle_register_driver);
  */
 void cpuidle_unregister_driver(struct cpuidle_driver *drv)
 {
-       if (!drv)
+       if (drv != cpuidle_curr_driver) {
+               WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
+                       drv->name);
                return;
+       }
 
        spin_lock(&cpuidle_driver_lock);
        cpuidle_curr_driver = NULL;