Comment 2 for bug 1214929

StacktraceTop:
 g_type_check_instance (type_instance=type_instance@entry=0x28962b0) at /build/buildd/glib2.0-2.37.5/./gobject/gtype.c:4082
 g_signal_emit_valist (instance=0x28962b0, signal_id=381, detail=0, var_args=var_args@entry=0x7fff95745c58) at /build/buildd/glib2.0-2.37.5/./gobject/gsignal.c:3105
 g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=detail@entry=0) at /build/buildd/glib2.0-2.37.5/./gobject/gsignal.c:3382
 position_provider_changed (proxy=<optimized out>, name=<optimized out>, description=<optimized out>, service=<optimized out>, path=<optimized out>, client=<optimized out>) at geoclue-master-client.c:172
 marshal_dbus_message_to_g_marshaller (closure=0x2bc6c10, return_value=0x0, n_param_values=<optimized out>, param_values=<optimized out>, invocation_hint=0x7fff95745f10, marshal_data=0x0) at dbus-gproxy.c:1736