On Mon, 17 Feb 2014 20:01:42 +0200
Marcel Apfelbaum <marce...@redhat.com> wrote:
> On Mon, 2014-02-17 at 10:38 -0700, Eric Blake wrote:
> > On 02/17/2014 04:52 AM, Marcel Apfelbaum wrote:
> > > A NULL value is not added to visitor's stack, but there
> > > is no check for that when the visitor tries to return
> > > that value, leading to Qemu crash.
> >
> > Do you have an easy formula for reproducing the crash?
>
> Hi Eric, thank you for your review!
>
> In order to reproduce this you need to use object_property_get_str
> on an object with a string property with a null value.
I tried looking into this but got a bit lost in the abstraction maze.
Can you point me to your series and how to reproduce it?
> I don't know if in the current code base we have this scenario, but
> I am trying to QOMify the QemuMachine and properties as "kernel" may be NULL.
>
> Either way (if NULL properties are not wanted), IMHO it is recommended to
> cover such cases in order to avoid QEMU crash.
I agree, but I want to be sure we're fixing the right thing and not only
papering over a bug. Also, Why is the check not needed in qmp_output_last()?
Btw, sorry for the long delay.
>
> >
> > >
> > > Signed-off-by: Marcel Apfelbaum <marce...@redhat.com>
> > > ---
> > > qapi/qmp-output-visitor.c | 5 +++++
> > > 1 file changed, 5 insertions(+)
> > >
> > > diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
> > > index 74a5684..0562f49 100644
> > > --- a/qapi/qmp-output-visitor.c
> > > +++ b/qapi/qmp-output-visitor.c
> > > @@ -66,6 +66,11 @@ static QObject *qmp_output_pop(QmpOutputVisitor *qov)
> > > static QObject *qmp_output_first(QmpOutputVisitor *qov)
> > > {
> > > QStackEntry *e = QTAILQ_LAST(&qov->stack, QStack);
> > > +
> > > + if (!e) {
> > > + return NULL;
> > > + }
> > > +
> >
> > The code looks okay to me, but without a formula, my review is fairly weak:
> Appreciated,
> Marcel
>
> >
> > Reviewed-by: Eric Blake <ebl...@redhat.com>
> >
>
>
>
