Re: [Qemu-devel] [PATCH] hw/hyperv: fix NULL dereference with pure-kvm SynIC

[Eduardo Habkost]

On Mon, Nov 26, 2018 at 06:13:49PM +0100, Paolo Bonzini wrote:
> On 26/11/18 16:28, Roman Kagan wrote:
> > When started in compat configuration of SynIC, e.g.
> > 
> > qemu-system-x86_64 -machine pc-i440fx-2.10,accel=kvm \
> >  -cpu host,-vmx,hv-relaxed,hv_spinlocks=0x1fff,hv-vpindex,hv-synic
> > 
> > or explicitly
> > 
> > qemu-system-x86_64 -enable-kvm -cpu host,hv-synic,x-hv-synic-kvm-only=on
> > 
> > QEMU crashes in hyperv_synic_reset() trying to access the non-present
> > qobject for SynIC.
> > 
> > Add the missing check for NULL.
> > 
> > Reported-by: Vitaly Kuznetsov <address@hidden>
> > Reported-by: Igor Mammedov <address@hidden>
> > Fixes: 9b4cf107b09d18ac30f46fd1c4de8585ccba030c
> > Fixes: 4a93722f9c279184e95b1e1ad775c01deec05065
> > Signed-off-by: Roman Kagan <address@hidden>
> > ---
> >  hw/hyperv/hyperv.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c
> > index a28e7249d8..8758635227 100644
> > --- a/hw/hyperv/hyperv.c
> > +++ b/hw/hyperv/hyperv.c
> > @@ -136,7 +136,11 @@ void hyperv_synic_add(CPUState *cs)
> >  
> >  void hyperv_synic_reset(CPUState *cs)
> >  {
> > -    device_reset(DEVICE(get_synic(cs)));
> > +    SynICState *synic = get_synic(cs);
> > +
> > +    if (synic) {
> > +        device_reset(DEVICE(synic));
> > +    }
> >  }
> >  
> >  static const TypeInfo synic_type_info = {
> > 
> 
> Queued, thanks.

Oops, I had queued it earlier today and just submitted a pull
request.

-- 
Eduardo