Messages in this thread |  | | | Date | Fri, 8 Feb 2008 21:15:39 -0800 | | From | Greg KH <> | | Subject | Re: kobject must be initialized before calling kobject_init()?! | |
On Fri, Feb 08, 2008 at 08:24:25PM -0800, Roland Dreier wrote:
> So I was perusing the code in lib/kobject.c, and I saw this:
> > void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
> {
> // [a couple of of parameter checks...]
> if (kobj->state_initialized) {
> /* do not error out as sometimes we can recover */
> printk(KERN_ERR "kobject (%p): tried to init an initialized "
> "object, something is seriously wrong.\n", kobj);
> dump_stack();
> }
>
> in other words the first thing you do is check a member of the
> structure you're supposed to be initializing -- if someone just
> kmalloc()s a struct kobject and passes it into this function, there's
> a good chance that state_initialized won't be zero. In fact, with
> slab debugging on, it's guaranteed to be poisoned with a non-zero
> value.
>
> So are users supposed to be zeroing out struct kobjects before
> initializing them?
Yes. See also the check about the non-zero reference count when
initializing the kref, that too will trip.
> If so, this should probably be documented.
You're right. Patches gladly accepted :)
thanks,
greg k-h
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