hwmon: Fix a potential race condition on unload
Fix a potential race condition when some hardware monitoring platform
drivers are being unloaded. I believe that the driver data pointer
shouldn't be cleared before all the sysfs files are removed, otherwise
a sysfs callback might attempt to dereference a NULL pointer. I'm not
sure exactly what the driver core protects drivers against, so let's
play it safe.
While we're here, clear the driver data pointer when probe fails, so
as to not leave an invalid pointer behind us.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
diff --git a/drivers/hwmon/smsc47m1.c b/drivers/hwmon/smsc47m1.c
index 9bac3c2..1de2f2b 100644
--- a/drivers/hwmon/smsc47m1.c
+++ b/drivers/hwmon/smsc47m1.c
@@ -597,6 +597,7 @@
error_remove_files:
sysfs_remove_group(&dev->kobj, &smsc47m1_group);
error_free:
+ platform_set_drvdata(pdev, NULL);
kfree(data);
error_release:
release_region(res->start, SMSC_EXTENT);
@@ -608,12 +609,12 @@
struct smsc47m1_data *data = platform_get_drvdata(pdev);
struct resource *res;
- platform_set_drvdata(pdev, NULL);
hwmon_device_unregister(data->class_dev);
sysfs_remove_group(&pdev->dev.kobj, &smsc47m1_group);
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
release_region(res->start, SMSC_EXTENT);
+ platform_set_drvdata(pdev, NULL);
kfree(data);
return 0;
