Re: [PATCH] nubus: switch to dynamic root device

[Finn Thain <fthain@linux-m68k.org>]

On Mon, 27 Apr 2026, Johan Hovold wrote:

> On Sat, Apr 25, 2026 at 02:07:10PM +1000, Finn Thain wrote:
> > On Fri, 24 Apr 2026, Johan Hovold wrote:
> > 
> > > Driver core expects devices to be dynamically allocated and will, 
> > > for example, complain loudly if a device that lacks a release 
> > > function is ever freed.
> > > 
> > 
> > Yes, in drivers/base/core.c, there is a warning in device_release().
> > 
> > WARN(1, KERN_ERR "Device '%s' does not have a release()
> > 	function, it is broken and must be fixed. See 
> > 	Documentation/core-api/kobject.rst.\n",
> > 
> > But there's no way for the refcount for the nubus parent device to 
> > reach zero that I can see. Did I miss something?
> 
> It will if registration ever fails (e.g. due to fault injection or name 
> collision):
> 
> 	err = device_register(&nubus_parent);
> 	if (err) {
> 		put_device(&nubus_parent);
> 		return err;
> 	}
> 

In that situation the kernel error message would say the device "is broken 
and must be fixed" when it was deliberately broken by fault injection.
I think the commit log should state that the aim of your patch is to avoid 
that error message for that use-case.
Aside from that quibble, the patch looks fine to me.

Acked-by: Finn Thain <fthain@linux-m68k.org>