From ff99aaab25525aafcb789e0f8b3bc569f14e982e Mon Sep 17 00:00:00 2001
From: Sam Gross <colesbury@gmail.com>
Date: Fri, 20 Mar 2026 15:38:35 -0400
Subject: [PATCH] [3.13] gh-146227: Fix wrong type in _Py_atomic_load_uint16 in
 pyatomic_std.h (gh-146229)

Also fix a few related issues in the pyatomic headers:

* Fix _Py_atomic_store_uint_release in pyatomic_msc.h to use __stlr32
  on ARM64 instead of a plain volatile store (which is only relaxed on
  ARM64).

* Add missing _Py_atomic_store_uint_release to pyatomic_gcc.h.

* Fix pseudo-code comment for _Py_atomic_store_ptr_release in
  pyatomic.h.
(cherry picked from commit 1eff27f2c0452b3114bcf139062c87c025842c3e)

Co-authored-by: Sam Gross <colesbury@gmail.com>
---
 Include/cpython/pyatomic.h                                    | 4 ++--
 Include/cpython/pyatomic_std.h                                | 2 +-
 .../2026-03-20-13-07-33.gh-issue-146227.MqBPEo.rst            | 3 +++
 3 files changed, 6 insertions(+), 3 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-03-20-13-07-33.gh-issue-146227.MqBPEo.rst

diff --git a/Include/cpython/pyatomic.h b/Include/cpython/pyatomic.h
index 28029859d3df2b..71e91c8964b981 100644
--- a/Include/cpython/pyatomic.h
+++ b/Include/cpython/pyatomic.h
@@ -72,8 +72,8 @@
 //   def _Py_atomic_load_ptr_acquire(obj):
 //       return obj  # acquire
 //
-//   def _Py_atomic_store_ptr_release(obj):
-//       return obj  # release
+//   def _Py_atomic_store_ptr_release(obj, value):
+//       obj = value  # release
 //
 //   def _Py_atomic_fence_seq_cst():
 //       # sequential consistency
diff --git a/Include/cpython/pyatomic_std.h b/Include/cpython/pyatomic_std.h
index 7c71e94c68f8e6..ab3a4e1c74cd64 100644
--- a/Include/cpython/pyatomic_std.h
+++ b/Include/cpython/pyatomic_std.h
@@ -459,7 +459,7 @@ static inline uint16_t
 _Py_atomic_load_uint16(const uint16_t *obj)
 {
     _Py_USING_STD;
-    return atomic_load((const _Atomic(uint32_t)*)obj);
+    return atomic_load((const _Atomic(uint16_t)*)obj);
 }
 
 static inline uint32_t
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-03-20-13-07-33.gh-issue-146227.MqBPEo.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-20-13-07-33.gh-issue-146227.MqBPEo.rst
new file mode 100644
index 00000000000000..11e19eb28313d6
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-20-13-07-33.gh-issue-146227.MqBPEo.rst
@@ -0,0 +1,3 @@
+Fix wrong type in ``_Py_atomic_load_uint16`` in the C11 atomics backend
+(``pyatomic_std.h``), which used a 32-bit atomic load instead of 16-bit.
+Found by Mohammed Zuhaib.