From d9c26676b26ab09d8db7265dc22a733d3c358d4b Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Fri, 13 Mar 2026 13:45:18 +0100
Subject: [PATCH] [3.14] gh-145792: Fix incorrect alloca allocation size in
 traceback.c (GH-145814) (#145909)

gh-145792: Fix incorrect alloca allocation size in traceback.c (GH-145814)
(cherry picked from commit 59d97683c19923b06e2b2110efadb90fe37f53f3)

Co-authored-by: VanshAgarwal24036 <148854295+VanshAgarwal24036@users.noreply.github.com>
---
 .../2026-03-11-19-09-47.gh-issue-145792.X5KUhc.rst              | 2 ++
 Python/traceback.c                                              | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-03-11-19-09-47.gh-issue-145792.X5KUhc.rst

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-03-11-19-09-47.gh-issue-145792.X5KUhc.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-11-19-09-47.gh-issue-145792.X5KUhc.rst
new file mode 100644
index 00000000000..bd42f32d6ae
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-11-19-09-47.gh-issue-145792.X5KUhc.rst
@@ -0,0 +1,2 @@
+Fix out-of-bounds access when invoking faulthandler on a CPython build
+compiled without support for VLAs.
diff --git a/Python/traceback.c b/Python/traceback.c
index b9c9132c0c5..c8c13d16d4c 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -42,7 +42,7 @@
 
 #if defined(__STDC_NO_VLA__) && (__STDC_NO_VLA__ == 1)
 /* Use alloca() for VLAs. */
-#  define VLA(type, name, size) type *name = alloca(size)
+#  define VLA(type, name, size) type *name = alloca(sizeof(type) * (size))
 #elif !defined(__STDC_NO_VLA__) || (__STDC_NO_VLA__ == 0)
 /* Use actual C VLAs.*/
 #  define VLA(type, name, size) type name[size]