Re: [PATCH] software node: balance refcount for managed sw nodes

Jon Nettleton
2021-07-16T17:22:37Z

On Fri, Jul 16, 2021 at 2:17 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Fri, Jul 16, 2021 at 01:16:02PM +0300, laurentiu.tudor@nxp.com wrote:
> > From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> >
> > software_node_notify(), on KOBJ_REMOVE drops the refcount twice on managed
> > software nodes, thus leading to underflow errors. Balance the refcount by
> > bumping it in the device_create_managed_software_node() function.
> >
> > The error [1] was encountered after adding a .shutdown() op to our
> > fsl-mc-bus driver.
>
> Looking into the history of adding ->shutdown() to dwc3 driver (it got reverted
> later on), I can tell that probably something is wrong in the ->shutdown()
> method itself.
>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Isn't the other alternative to just remove the second kobject_put from
KOBJ_REMOVE ?

@@ -1149,7 +1147,6 @@ int software_node_notify(struct device *dev,
unsigned long action)

if (swnode->managed) {
set_secondary_fwnode(dev, NULL);
- kobject_put(&swnode->kobj);
}
break;
default:

If we aren't being incremented in device_create_managed_software_node() then
should we be decremented here?

-Jon