[PATCH] Driver core: potentially fix use after free in class_device_attr_show
This moves the code to free devt_attr from class_device_del() to
class_dev_release() which is called after the last reference to the
corresponding kobject() is gone.
This allows us to keep the devt_attr alive while the corresponding
sysfs file is open.
Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 479c125..0154a16 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -299,6 +299,11 @@
pr_debug("device class '%s': release.\n", cd->class_id);
+ if (cd->devt_attr) {
+ kfree(cd->devt_attr);
+ cd->devt_attr = NULL;
+ }
+
if (cls->release)
cls->release(cd);
else {
@@ -591,11 +596,8 @@
if (class_dev->dev)
sysfs_remove_link(&class_dev->kobj, "device");
- if (class_dev->devt_attr) {
+ if (class_dev->devt_attr)
class_device_remove_file(class_dev, class_dev->devt_attr);
- kfree(class_dev->devt_attr);
- class_dev->devt_attr = NULL;
- }
class_device_remove_attrs(class_dev);
kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);