[PATCH] kobject: make sure kobj->ktype is set before kobject_init

Alan Stern
2007-11-28T20:42:17Z

This patch (as1020) adds a check to kobject_init() to insure that the
ktype field is not NULL. This is just for safety's sake; as far as I
know there are no remaining places where the field is left unset. But
ironically, kset_init() did fail to set it! The patch fixes that and
removes some redundant initialization in kset_createa().

The patch also fixes up elevator_init(), where ktype was set after
calling kobject_init() instead of before.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay.sievers@vrfy.org>

---

Here is the check we discussed. I'm a little behind on Kay's most
recent updates; I hope this doesn't clash with them.

There may be some other places where ktype gets set after
kobject_init() rather than before. My testing can't be termendously
thorough. But they should all be easy to fix (like elevator.c was).

Index: usb-2.6/lib/kobject.c
===================================================================
--- usb-2.6.orig/lib/kobject.c
+++ usb-2.6/lib/kobject.c
@@ -188,6 +188,7 @@ void kobject_init(struct kobject * kobj)
return;
WARN_ON(atomic_read(&kobj->kref.refcount));
verify_dynamic_kobject_allocation(kobj);
+ WARN_ON(!kobj->ktype);
kref_init(&kobj->kref);
INIT_LIST_HEAD(&kobj->entry);
kobj->kset = kset_get(kobj->kset);
@@ -624,18 +625,6 @@ struct kobject *kobject_create_and_regis
}
EXPORT_SYMBOL_GPL(kobject_create_and_register);

-/**
- * kset_init - initialize a kset for use
- * @k: kset
- */
-
-void kset_init(struct kset * k)
-{
- kobject_init(&k->kobj);
- INIT_LIST_HEAD(&k->list);
- spin_lock_init(&k->list_lock);
-}
-
/* default kobject attribute operations */
static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf)
@@ -751,6 +740,19 @@ static struct kobj_type kset_ktype = {
};

/**
+ * kset_init - initialize a kset for use
+ * @k: kset
+ */
+
+void kset_init(struct kset * k)
+{
+ k->kobj.ktype = &kset_ktype;
+ kobject_init(&k->kobj);
+ INIT_LIST_HEAD(&k->list);
+ spin_lock_init(&k->list_lock);
+}
+
+/**
* kset_create - create a struct kset dynamically
*
* @name: the name for the kset
@@ -779,12 +781,10 @@ static struct kset *kset_create(const ch
kset->kobj.parent = parent_kobj;

/*
- * The kobject of this kset will have a type of kset_ktype and belong to
- * no kset itself. That way we can properly free it when it is
+ * The kobject of this kset will have a type of kset_ktype and belong
+ * to no kset itself. That way we can properly free it when it is
* finished being used.
*/
- kset->kobj.ktype = &kset_ktype;
- kset->kobj.kset = NULL;

return kset;
}
Index: usb-2.6/block/elevator.c
===================================================================
--- usb-2.6.orig/block/elevator.c
+++ usb-2.6/block/elevator.c
@@ -185,9 +185,9 @@ static elevator_t *elevator_alloc(struct

eq->ops = &e->ops;
eq->elevator_type = e;
- kobject_init(&eq->kobj);
kobject_set_name(&eq->kobj, "%s", "iosched");
eq->kobj.ktype = &elv_ktype;
+ kobject_init(&eq->kobj);
mutex_init(&eq->sysfs_lock);

eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES,