pc: fix possible NULL pointer dereference in pc_machine_get_device_memory_region_size()

QEMU will crash when device-memory-region-size property is read if ms->device_memory
wasn't initialized yet.

Crash can be reproduced with:
 $QEMU -preconfig -qmp unix:qmp_socket,server,nowait &
 ./scripts/qmp/qom-get -s qmp_socket /machine.device-memory-region-size

Instead of crashing return 0 if ms->device_memory hasn't been initialized.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1560174635-22602-1-git-send-email-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Igor Mammedov 2019-06-10 15:50:35 +02:00 committed by Paolo Bonzini
parent 39d1b92b81
commit 58164eaff5

View file

@ -2458,7 +2458,11 @@ pc_machine_get_device_memory_region_size(Object *obj, Visitor *v,
Error **errp)
{
MachineState *ms = MACHINE(obj);
int64_t value = memory_region_size(&ms->device_memory->mr);
int64_t value = 0;
if (ms->device_memory) {
value = memory_region_size(&ms->device_memory->mr);
}
visit_type_int(v, name, &value, errp);
}