Address review: use seq-cst atomics for initialized flags

Not performance critical, so use the default ordering rather than
acquire/release.

Author: gpshead

Include/internal/pycore_runtime.h

@@ -56,27 +56,27 @@ _PyRuntimeState_SetFinalizing(_PyRuntimeState *runtime, PyThreadState *tstate) {
     }
 }
 
-// Release on store, acquire on load: a thread that reads initialized=1
-// is guaranteed to observe all writes from the initialization sequence.
+// Atomic so a thread that reads initialized=1 observes all writes
+// from the initialization sequence (gh-146302).
 
 static inline int
 _PyRuntimeState_GetCoreInitialized(_PyRuntimeState *runtime) {
-    return _Py_atomic_load_int_acquire(&runtime->core_initialized);
+    return _Py_atomic_load_int(&runtime->core_initialized);
 }
 
 static inline void
 _PyRuntimeState_SetCoreInitialized(_PyRuntimeState *runtime, int initialized) {
-    _Py_atomic_store_int_release(&runtime->core_initialized, initialized);
+    _Py_atomic_store_int(&runtime->core_initialized, initialized);
 }
 
 static inline int
 _PyRuntimeState_GetInitialized(_PyRuntimeState *runtime) {
-    return _Py_atomic_load_int_acquire(&runtime->initialized);
+    return _Py_atomic_load_int(&runtime->initialized);
 }
 
 static inline void
 _PyRuntimeState_SetInitialized(_PyRuntimeState *runtime, int initialized) {
-    _Py_atomic_store_int_release(&runtime->initialized, initialized);
+    _Py_atomic_store_int(&runtime->initialized, initialized);
 }
 
 

Misc/NEWS.d/next/C_API/2026-03-22-00-00-00.gh-issue-146302.PyIsInit.rst

@@ -1,3 +1,3 @@
 :c:func:`Py_IsInitialized` no longer returns true until initialization has
 fully completed, including import of the :mod:`site` module.  The underlying
-runtime flags now use atomic operations with acquire/release memory ordering.
+runtime flags now use atomic operations.