On Fri, Jun 24, 2022 at 05:59:58PM +0530, Kirti Wankhede wrote:
> > The reason this is here is because the type->parent is used in a few
> > places and is put back in release:
> >
> > @@ -81,7 +81,7 @@ static void mdev_type_release(struct kobject *kobj)
> >
> > pr_debug("Releasing group %s\n", kobj->name);
> > /* Pairs with the get in add_mdev_supported_type() */
> > - mdev_put_parent(type->parent);
> > + put_device(type->parent->dev);
> > kfree(type);
> > }
> >
> > If this was a simple sysfs kobj with only a show/store we wouldn't
> > need to do anything as the natural kobj parentage holds a ref up to
> > the struct device - but this kobj is used internally, ie dependent
> > from mdev_device_create(), independently of the normal sysfs
> > life-cycle so that doesn't protect enough either.
> >
>
>
> Life span of 'type' is from mdev_register_device to mdev_unregister_device.
> If device/parent is being unregistered then only types are removed, so
> referencing 'type' from mdev_device_create() is still safe. Therefore,
> parent device's reference should be held and release from
> register-unregister call.
No, I've already explained this.
Jason
