[Python-checkins] Fix a possible decref of a borrowed reference in symtable.c. (GH-9786)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/1a23abed1340c44e0296d9963487443f63aea225
commit: 1a23abed1340c44e0296d9963487443f63aea225
branch: 3.6
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-10-10T22:28:08-07:00
summary:

Fix a possible decref of a borrowed reference in symtable.c. (GH-9786)

(cherry picked from commit fc439d20de32b0ebccca79a96e31f83b85ec4eaf)

Co-authored-by: Zackery Spytz <zspytz at gmail.com>

files:
M Python/symtable.c

diff --git a/Python/symtable.c b/Python/symtable.c
index 6165cfe162ea..90b07efa0334 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -628,8 +628,10 @@ update_symbols(PyObject *symbols, PyObject *scopes,
         return 0;
 
     itr = PyObject_GetIter(free);
-    if (!itr)
-        goto error;
+    if (itr == NULL) {
+        Py_DECREF(v_free);
+        return 0;
+    }
 
     while ((name = PyIter_Next(itr))) {
         v = PyDict_GetItem(symbols, name);