diff --git a/hmp.c b/hmp.c
index 2bc4f062bb0dff78526bae1ec4e8a997d6a9d5a1..0c805967e682c05f9a6561e2f2d3529e00d7d534 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1552,6 +1552,7 @@ void hmp_block_set_io_throttle(Monitor *mon, const QDict *qdict)
 {
     Error *err = NULL;
     BlockIOThrottle throttle = {
+        .has_device = true,
         .device = (char *) qdict_get_str(qdict, "device"),
         .bps = qdict_get_int(qdict, "bps"),
         .bps_rd = qdict_get_int(qdict, "bps_rd"),