regulator: Fix deadlock on removal of regulators with supplies
Mark Brown [Wed, 28 Mar 2012 20:17:55 +0000 (21:17 +0100)]
If a regulator with a supply is being unregistered we will call
regulator_put() to release the supply with the regulator_list_mutex held
but this deadlocks as regulator_put() takes the same lock. Fix this by
releasing the supply before we take the mutex in regulator_unregister().

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/core.c

index e2f3afa..4a5054e 100644 (file)
@@ -2992,14 +2992,14 @@ void regulator_unregister(struct regulator_dev *rdev)
        if (rdev == NULL)
                return;
 
+       if (rdev->supply)
+               regulator_put(rdev->supply);
        mutex_lock(&regulator_list_mutex);
        debugfs_remove_recursive(rdev->debugfs);
        flush_work_sync(&rdev->disable_work.work);
        WARN_ON(rdev->open_count);
        unset_regulator_supplies(rdev);
        list_del(&rdev->list);
-       if (rdev->supply)
-               regulator_put(rdev->supply);
        kfree(rdev->constraints);
        device_unregister(&rdev->dev);
        mutex_unlock(&regulator_list_mutex);