Re: QEMU device refcounting when device creates a container MR

[Peter Maydell]

On Thu, 10 Mar 2022 at 15:36, Igor Mammedov <imammedo@redhat.com> wrote:
>
> On Wed, 9 Mar 2022 16:56:21 +0000
> Peter Maydell <peter.maydell@linaro.org> wrote:
> > ...also, in the device-introspect-test where I see this problem,
> > unrealize is never going to be called anyway, because the device
> > is only put through "instance_init" and then dereffed (which
> > does not result in instance_finalize being called, because the
> > refcount is still non-zero).
>
> question is why introspected device is deferred instead of being
> destroyed if it's no longer needed?

...because the reference count is not zero.

What is supposed to happen is:
 * device is created (inited), and has refcount of 1
 * introspection code does its thing
 * introspection code derefs the device, and it gets deinited

This bug means that when the device is inited it has a refcount
that is too high, and so despite the code that creates it
correctly dereffing it, it's still lying around.

thanks
-- PMM