From ed1007c0d74e658d1e6c9b51b12ce7501eb8cbf9 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 21 Nov 2020 19:17:46 +0200
Subject: [PATCH] bpo-42425: Fix possible leak in initialization of errmap for
 OSError (GH-23446)

---
 Objects/exceptions.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index b14da20db0c..d4824938a0f 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2547,8 +2547,10 @@ _PyExc_Init(PyThreadState *tstate)
     do { \
         PyObject *_code = PyLong_FromLong(CODE); \
         assert(_PyObject_RealIsSubclass(PyExc_ ## TYPE, PyExc_OSError)); \
-        if (!_code || PyDict_SetItem(state->errnomap, _code, PyExc_ ## TYPE)) \
+        if (!_code || PyDict_SetItem(state->errnomap, _code, PyExc_ ## TYPE)) { \
+            Py_XDECREF(_code); \
             return _PyStatus_ERR("errmap insertion problem."); \
+        } \
         Py_DECREF(_code); \
     } while (0)