Re: [PATCH v4 2/3] mac_via: fix incorrect creation of mos6522 device in mac_via

[Markus Armbruster]

Peter Maydell <address@hidden> writes:

> On Mon, 9 Mar 2020 at 10:02, Pan Nengyuan <address@hidden> wrote:
>> On 3/9/2020 5:21 PM, Peter Maydell wrote:
>> > Could you explain more? My thought is that we should be using
>> > sysbus_init_child_obj() and we should be doing it in the init method.
>> > Why does that break the tests ? It's the same thing various other
>> > devices do.
>>
>> device-introspect-test do the follow check for each device type:
>>
>>     qtree_start = qtest_hmp(qts, "info qtree");
>>     ...
>>     qtest_qmp(qts, "{'execute': 'device-list-properties','arguments': 
>> {'typename': %s}}", type);
>>     ...
>>     qtree_end = qtest_hmp(qts, "info qtree");
>>     g_assert_cmpstr(qtree_start, ==, qtree_end);
>>
>> If we do qdev_set_parent_bus in init, it will check fail when type = 
>> 'mac_via'.
>> mac_via_init() is called by q800_init(). But it will not be called in 
>> qtest(-machine none) in the step qtree_start.
>> And after we call 'device-list-properties', mac_via_init() was called and 
>> set dev parent bus. We can find these
>> devices in the qtree_end. So it break the test on the assert.
>
> Markus, do you know what's happening here? Why is
> trying to use sysbus_init_child_obj() breaking the
> device-introspect-test for this particular device,
> but fine for the other places where we use it?
> (Maybe we're accidentally leaking a reference to
> something so the sub-device stays on the sysbus
> when it should have removed itself when the
> device was deinited ?)

Pan Nengyuan, please provide the exact patch that fails for you.