From 41ad2bb2489c4cf9ba4f13401750b3fcdb33937b Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@microsoft.com>
Date: Tue, 28 Jan 2025 16:26:46 -0800
Subject: [PATCH] GH-128563: Don't leave frame->lltrace uninitialized
 (GH-129417)

---
 Include/internal/pycore_frame.h                             | 6 ++++++
 .../2025-01-28-11-13-41.gh-issue-128563.xElppE.rst          | 2 ++
 2 files changed, 8 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2025-01-28-11-13-41.gh-issue-128563.xElppE.rst

diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
index 155a6f3ce05..f6f2776804e 100644
--- a/Include/internal/pycore_frame.h
+++ b/Include/internal/pycore_frame.h
@@ -215,6 +215,9 @@ _PyFrame_Initialize(
     frame->return_offset = 0;
     frame->owner = FRAME_OWNED_BY_THREAD;
     frame->visited = 0;
+#ifdef Py_DEBUG
+    frame->lltrace = 0;
+#endif
 
     for (int i = null_locals_from; i < code->co_nlocalsplus; i++) {
         frame->localsplus[i] = PyStackRef_NULL;
@@ -398,6 +401,9 @@ _PyFrame_PushTrampolineUnchecked(PyThreadState *tstate, PyCodeObject *code, int
 #endif
     frame->owner = FRAME_OWNED_BY_THREAD;
     frame->visited = 0;
+#ifdef Py_DEBUG
+    frame->lltrace = 0;
+#endif
     frame->return_offset = 0;
 
 #ifdef Py_GIL_DISABLED
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-01-28-11-13-41.gh-issue-128563.xElppE.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-01-28-11-13-41.gh-issue-128563.xElppE.rst
new file mode 100644
index 00000000000..dfd932e836b
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-01-28-11-13-41.gh-issue-128563.xElppE.rst
@@ -0,0 +1,2 @@
+Fix an issue where the "lltrace" debug feature could have been incorrectly
+enabled for some frames.