Fixed possible NULL decrefing.

diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 2a652b06a22d8404d4ab1407adeea7bd000a6699..46cc64d62e250bed4baae83ab6b1f6eba3ae7348 100644 (file)
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -1874,7 +1874,7 @@ var_perform(VarEvent *ev)
         PyErr_NormalizeException(&exc, &val, &tb);
         *(ev->exc_type) = exc;
         *(ev->exc_val) = val;
-        Py_DECREF(tb);
+        Py_XDECREF(tb);
     }
 
 }