diff --git a/iothread.c b/iothread.c
index 44c8944dc4ed023874d1f65fafd57df241a1216a..59d08509883fdb779222c654dd3cdd75efbca483 100644
--- a/iothread.c
+++ b/iothread.c
@@ -85,7 +85,7 @@ static int iothread_stop(Object *object, void *opaque)
     IOThread *iothread;
 
     iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
-    if (!iothread || !iothread->ctx) {
+    if (!iothread || !iothread->ctx || iothread->stopping) {
         return 0;
     }
     iothread->stopping = true;