From 8fb36494501aad5b0c1d34311c9743c60bb9926c Mon Sep 17 00:00:00 2001
From: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com>
Date: Sat, 29 Jan 2022 22:34:12 +0800
Subject: [PATCH] fFx refleak in isinstance error path (GH-31005)

---
 Python/ceval.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Python/ceval.c b/Python/ceval.c
index fa14a1c04f1..b69d5aa9d32 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4946,6 +4946,7 @@ handle_eval_breaker:
             PyObject *inst = TOP();
             int retval = PyObject_IsInstance(inst, cls);
             if (retval < 0) {
+                Py_DECREF(cls);
                 goto error;
             }
             PyObject *res = PyBool_FromLong(retval);