changeset:   103045:3e4452424f9b
branch:      3.5
parent:      103042:4e0f56794a73
user:        Benjamin Peterson <benjamin@python.org>
date:        Mon Sep 05 10:39:57 2016 -0700
files:       Misc/NEWS Objects/genobject.c
description:
clear out f_gen during generator finalization (closes #27812)

Patch from Armin Rigo.


diff -r 4e0f56794a73 -r 3e4452424f9b Misc/NEWS
--- a/Misc/NEWS	Mon Sep 05 10:17:22 2016 -0700
+++ b/Misc/NEWS	Mon Sep 05 10:39:57 2016 -0700
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #27812: Properly clear out a generator's frame's backreference to the
+  generator to prevent crashes in frame.clear().
+
 - Issue #27811: Fix a crash when a coroutine that has not been awaited is
   finalized with warnings-as-errors enabled.
 
diff -r 4e0f56794a73 -r 3e4452424f9b Objects/genobject.c
--- a/Objects/genobject.c	Mon Sep 05 10:17:22 2016 -0700
+++ b/Objects/genobject.c	Mon Sep 05 10:39:57 2016 -0700
@@ -71,7 +71,10 @@
         return;                     /* resurrected.  :( */
 
     _PyObject_GC_UNTRACK(self);
-    Py_CLEAR(gen->gi_frame);
+    if (gen->gi_frame != NULL) {
+        gen->gi_frame->f_gen = NULL;
+        Py_CLEAR(gen->gi_frame);
+    }
     Py_CLEAR(gen->gi_code);
     Py_CLEAR(gen->gi_name);
     Py_CLEAR(gen->gi_qualname);