Re: [PATCH v3 5/6] hw/misc/mos6522: move timer_new from init() into realize() to avoid memleaks

[Mark Cave-Ayland]

On 02/03/2020 13:21, Peter Maydell wrote:

> On Thu, 27 Feb 2020 at 02:35, Pan Nengyuan <address@hidden> wrote:
>>
>> There are some memleaks when we call 'device_list_properties'. This patch 
>> move timer_new from init into realize to fix it.
>> Meanwhile, add calls to mos6522_realize() in mac_via_realize to make this 
>> move to be valid.
>>
>> Reported-by: Euler Robot <address@hidden>
>> Signed-off-by: Pan Nengyuan <address@hidden>
>> ---
>> Cc: Laurent Vivier <address@hidden>
>> ---
>> v2->v1:
>> - no changes in this patch.
>> v3->v2:
>> - remove null check in reset, and add calls to mos6522_realize() in 
>> mac_via_realize to make this move to be valid.
> 
> Hi; this is really fixing two bugs in one patch:
> 
>> ---
>>  hw/misc/mac_via.c | 5 +++++
>>  hw/misc/mos6522.c | 6 ++++++
>>  2 files changed, 11 insertions(+)
>>
>> diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
>> index b7d0012794..1d72d4ef35 100644
>> --- a/hw/misc/mac_via.c
>> +++ b/hw/misc/mac_via.c
>> @@ -879,6 +879,11 @@ static void mac_via_realize(DeviceState *dev, Error 
>> **errp)
>>      sysbus_init_child_obj(OBJECT(dev), "via2", &m->mos6522_via2,
>>                            sizeof(m->mos6522_via2), TYPE_MOS6522_Q800_VIA2);
>>
>> +    object_property_set_bool(OBJECT(&m->mos6522_via1), true, "realized",
>> +                             &error_abort);
>> +    object_property_set_bool(OBJECT(&m->mos6522_via2), true, "realized",
>> +                             &error_abort);
>> +
>>      /* Pass through mos6522 output IRQs */
>>      ms = MOS6522(&m->mos6522_via1);
>>      object_property_add_alias(OBJECT(dev), "irq[0]", OBJECT(ms),
> 
> This is fixing a bug in mac_via where it failed to actually
> realize devices it was using. That's a dependency for the bug
> you're trying to fix, but it's a separate one and should be
> in its own patch.

Sigh. Thanks for this - I actually discovered this a little while back and have 
some
local patches to do the same, but due to lack of time I never managed to tidy 
them up
for submission.

> You also want to pass the error back up to the caller, rather
> than using error_abort. To do that, at the top of the function:
> 
>     Error *err = NULL;
> 
> and then here you can do:
>     object_property_set_bool(OBJECT(&m->mos6522_via1), true, "realized", 
> &err);
>     if (err) {
>         error_propagate(errp, err);
>         return;
>     }
> 
> The existing code which inits the mos6522 objects and
> calls object_property_add_alias on them which is in
> the mac_via realize function should be moved to the init
> function. (init should init child objects and set up
> properties; realize should realize them.)

And I believe at some point I had a patch lying around to do this too...

> This is all fixing the incorrect creation of the mos6522
> devices in mac_via (which has been wrong since the mac_via
> was first added in commit 6dca62a0000f9), so that can all
> be one patch I think.
> 
>> +static void mos6522_realize(DeviceState *dev, Error **errp)
>> +{
>> +    MOS6522State *s = MOS6522(dev);
>>
>>      s->timers[0].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer1, 
>> s);
>>      s->timers[1].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer2, 
>> s);
>> @@ -502,6 +507,7 @@ static void mos6522_class_init(ObjectClass *oc, void 
>> *data)
>>
>>      dc->reset = mos6522_reset;
>>      dc->vmsd = &vmstate_mos6522;
>> +    dc->realize = mos6522_realize;
>>      device_class_set_props(dc, mos6522_properties);
>>      mdc->parent_reset = dc->reset;
>>      mdc->set_sr_int = mos6522_set_sr_int;
> 
> The changes to hw/misc/mos_6522.c are good, but should be in
> their own patch.


ATB,

Mark.