From: Sam Gross <colesbury@gmail.com>
Date: Wed, 7 Jan 2026 22:56:14 +0000 (-0500)
Subject: gh-129824: Fix data race on `runtime->gilstate.check_enabled` (gh-143530)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f11f5ebfe6614de23918e2c0b7eedb3a12a14752;p=thirdparty%2FPython%2Fcpython.git

gh-129824: Fix data race on `runtime->gilstate.check_enabled` (gh-143530)
---

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 16fb43ea1914..88dbdb6d139c 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -2435,7 +2435,7 @@ new_interpreter(PyThreadState **tstate_p,
 
     /* Issue #10915, #15751: The GIL API doesn't work with multiple
        interpreters: disable PyGILState_Check(). */
-    runtime->gilstate.check_enabled = 0;
+    _Py_atomic_store_int_relaxed(&runtime->gilstate.check_enabled, 0);
 
     // XXX Might new_interpreter() have been called without the GIL held?
     PyThreadState *save_tstate = _PyThreadState_GET();
diff --git a/Python/pystate.c b/Python/pystate.c
index f605527598a8..23853f697924 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -2832,7 +2832,7 @@ int
 PyGILState_Check(void)
 {
     _PyRuntimeState *runtime = &_PyRuntime;
-    if (!runtime->gilstate.check_enabled) {
+    if (!_Py_atomic_load_int_relaxed(&runtime->gilstate.check_enabled)) {
         return 1;
     }