From: Irit Katriel <1055913+iritkatriel@users.noreply.github.com>
Date: Wed, 1 May 2024 20:51:40 +0000 (+0100)
Subject: gh-118272: set stacktop to 0 before freeing contents, to avoid access to invalid... 
X-Git-Tag: v3.13.0b1~173
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6763bfcc0fbab7895514c1f954d79a2555036323;p=thirdparty%2FPython%2Fcpython.git

gh-118272: set stacktop to 0 before freeing contents, to avoid access to invalid objects during GC (#118478)
---

diff --git a/Python/frame.c b/Python/frame.c
index ec390e7426ad..2bb128235720 100644
--- a/Python/frame.c
+++ b/Python/frame.c
@@ -98,10 +98,11 @@ void
 _PyFrame_ClearLocals(_PyInterpreterFrame *frame)
 {
     assert(frame->stacktop >= 0);
-    for (int i = 0; i < frame->stacktop; i++) {
+    int stacktop = frame->stacktop;
+    frame->stacktop = 0;
+    for (int i = 0; i < stacktop; i++) {
         Py_XDECREF(frame->localsplus[i]);
     }
-    frame->stacktop = 0;
     Py_CLEAR(frame->f_locals);
 }