diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
index 7a1376bf49a20a2437840cea18102a8d24524268..3ce21a8f5345ed86fc53d05d2c4810a9835dad0d 100644
--- a/src/rpc/virnetserver.c
+++ b/src/rpc/virnetserver.c
@@ -580,18 +580,21 @@ virJSONValuePtr virNetServerPreExecRestart(virNetServerPtr srv)
         goto error;
 
     if (virJSONValueObjectAppendNumberUint(object, "min_workers",
+                                           srv->workers == NULL ? 0 :
                                            virThreadPoolGetMinWorkers(srv->workers)) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Cannot set min_workers data in JSON document"));
         goto error;
     }
     if (virJSONValueObjectAppendNumberUint(object, "max_workers",
+                                           srv->workers == NULL ? 0 :
                                            virThreadPoolGetMaxWorkers(srv->workers)) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Cannot set max_workers data in JSON document"));
         goto error;
     }
     if (virJSONValueObjectAppendNumberUint(object, "priority_workers",
+                                           srv->workers == NULL ? 0 :
                                            virThreadPoolGetPriorityWorkers(srv->workers)) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Cannot set priority_workers data in JSON document"));