Re: [Qemu-devel] [PATCH 3/4] graphic_console_init: do not receive unneeded error descriptions

[Kirill Batuzov]

On Tue, 22 Apr 2014, Gerd Hoffmann wrote:

> > >     if (dev) {
> > > -        object_property_set_link(OBJECT(s), OBJECT(dev),
> > > -                                 "device", &local_err);
> > > -        object_property_set_int(OBJECT(s), head,
> > > -                                "head", &local_err);
> > > +        object_property_set_link(OBJECT(s), OBJECT(dev), "device", NULL);
> > > +        object_property_set_int(OBJECT(s), head, "head", NULL);
> > 
> > I guess it would be better to use &error_abort rather than failing
> > silently.
> 
> Agree.
>

The result of this change was a bit unexpected. QEMU fails to start
with the error "Insufficient permission to perform this operation". This
happens because "head" is a read-only property. Fortunately it is
usually (always?) zero at creation time and we always try to write zero
also. So it works somehow. But non-zero head will not work.

We need either to initialize it in new_console with right head value or
to change it to simple struct field. It depends entirely on our future
plans for it.

In v2 I also plan to change all occurrences of &local_err to &error_abort
in ui/console.c They all are unchecked and can cause memory leaks and/or
weird silent failures like setting of "head" property had.

-- 
Kirill