driver core: class: properly reference count class_dev_iter()

When class_dev_iter is initialized, the reference count for the subsys private structure is incremented, but never decremented, causing a memory leak over time. To resolve this, save off a pointer to the internal structure into the class_dev_iter structure and then when the iterator is finished, drop the reference count.

Greg Kroah-Hartman committed 3 years ago

Commit ddaf0981 parent 1e94be72 files · +3 −0Browse files

Unified · Split

2 files

drivers/base/class.c +2 −0
include/linux/device/class.h +1 −0

drivers/base/class.c+2−0

 		start_knode = &start->p->knode_class;
 	klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode);
 	iter->type = type;
+	iter->sp = sp;
 }
 EXPORT_SYMBOL_GPL(class_dev_iter_init);
 void class_dev_iter_exit(struct class_dev_iter *iter)
 {
 	klist_iter_exit(&iter->ki);
+	subsys_put(iter->sp);
 }
 EXPORT_SYMBOL_GPL(class_dev_iter_exit);

include/linux/device/class.h+1−0

@@ -74,6 +74,7 @@ struct class { · 73 unmodified lines
74	struct class_dev_iter {	74	struct class_dev_iter {
75	struct klist_iter ki;	75	struct klist_iter ki;
76	const struct device_type *type;	76	const struct device_type *type;
		77	struct subsys_private *sp;
77	};	78	};
78		79
79	int __must_check class_register(const struct class *class);	80	int __must_check class_register(const struct class *class);