From f032e9237aa7d43d21e0b04d685c36bddf7078c1 Mon Sep 17 00:00:00 2001
From: Zackery Spytz <Osmunda46@gmail.com>
Date: Thu, 7 Sep 2017 19:17:38 -0600
Subject: [PATCH] [3.6] bpo-30640: Fix undefined behavior in
 _PyFunction_FastCallDict() and PyEval_EvalCodeEx() (GH-2919) (#2964)

k + 1 was calculated with k = NULL..
(cherry picked from commit c6ea8974e2d939223bfd6d64ee13ec89c090d2e0)
---
 Python/ceval.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Python/ceval.c b/Python/ceval.c
index 8eb78bf4d46..4aa3250cd0b 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4171,7 +4171,8 @@ PyEval_EvalCodeEx(PyObject *_co, PyObject *globals, PyObject *locals,
 {
     return _PyEval_EvalCodeWithName(_co, globals, locals,
                                     args, argcount,
-                                    kws, kws + 1, kwcount, 2,
+                                    kws, kws != NULL ? kws + 1 : NULL,
+                                    kwcount, 2,
                                     defs, defcount,
                                     kwdefs, closure,
                                     NULL, NULL);
@@ -5053,7 +5054,7 @@ _PyFunction_FastCallDict(PyObject *func, PyObject **args, Py_ssize_t nargs,
 
     result = _PyEval_EvalCodeWithName((PyObject*)co, globals, (PyObject *)NULL,
                                       args, nargs,
-                                      k, k + 1, nk, 2,
+                                      k, k != NULL ? k + 1 : NULL, nk, 2,
                                       d, nd, kwdefs,
                                       closure, name, qualname);
     Py_XDECREF(kwtuple);