diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index caad326..8608776 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -9604,6 +9604,8 @@
     else if (maxcount == 0 || slen == 0)
         goto nothing;
 
+    if (str1 == str2)
+        goto nothing;
     if (skind < kind1)
         /* substring too wide to be present */
         goto nothing;