Re: [Qemu-devel] [PATCH v2 3/6] hw/arm: Use sysbus_init_child_obj for correct reference counting

[Peter Maydell]

On Fri, 23 Aug 2019 at 16:26, Thomas Huth <address@hidden> wrote:
>
> On 8/23/19 4:32 PM, Philippe Mathieu-Daudé wrote:
> > As explained in commit aff39be0ed97:
> >
> >   Both functions, object_initialize() and qdev_set_parent_bus()
>
> Commit aff39be0ed97 was not about qdev_set_parent_bus(), so the first
> sentence sounds somewhat misleading here. Maybe rephrase the commit
> message without that reference to aff39be0ed97 ?
>
> >   increase the reference counter of the new object, so one of the
> >   references has to be dropped afterwards to get the reference
> >   counting right. Otherwise the child object will not be properly
> >   cleaned up when the parent gets destroyed.
>
> Well, the parent here (the machine) currently never gets destroyed ...
> so unless you've got a patch in your pipe to fix that, too, you should
> maybe also rephrase this part of the commit message.

How about just making the commit message:

Both object_initialize() and qdev_set_parent_bus() increase the
reference counter of the new object, so one of the references has
to be dropped afterwards to get the reference counting right.
In machine model code this refcount leak is not particularly
problematic because (unlike devices) machines will never be
created on demand via QMP, and they are never destroyed.
But in any case let's use the new sysbus_init_child_obj() instead
to get the reference counting here right.

?

thanks
-- PMM