From: Roman Kagan <rkagan@xxxxxxxxxxxxx> 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 <vkuznets@xxxxxxxxxx> Reported-by: Igor Mammedov <imammedo@xxxxxxxxxx> Fixes: 9b4cf107b09d18ac30f46fd1c4de8585ccba030c Fixes: 4a93722f9c279184e95b1e1ad775c01deec05065 Signed-off-by: Roman Kagan <rkagan@xxxxxxxxxxxxx> Message-Id: <20181126152836.25379-1-rkagan@xxxxxxxxxxxxx> Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> Tested-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> Signed-off-by: Eduardo Habkost <ehabkost@xxxxxxxxxx> --- 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 = { -- 2.18.0.rc1.1.g3f1ff2140