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>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 2257004fe33d..826b5c0aa12b 100644
--- 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;