From: Edward Xu <xuxiangad@gmail.com>
Date: Mon, 3 Aug 2026 15:20:39 +0000 (+0800)
Subject: gh-154937: Fix `_thread._shutdown()` racing with `_thread.start_joinable_thread`... 
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a4095ee272f5e5082281a94a0856dde3c2f323f9;p=thirdparty%2FPython%2Fcpython.git

gh-154937: Fix `_thread._shutdown()` racing with `_thread.start_joinable_thread` on `ThreadHandle.ident` (#155085)
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-08-02-17-55-29.gh-issue-154937.m9IBba.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-02-17-55-29.gh-issue-154937.m9IBba.rst
new file mode 100644
index 000000000000..475dc8358a8d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-02-17-55-29.gh-issue-154937.m9IBba.rst
@@ -0,0 +1,3 @@
+Fix a data race on thread handle identifiers when ``_thread._shutdown()``
+runs concurrently with the startup of non-daemon threads in the
+:term:`free-threaded build`.
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index e999fe20287e..199e4ac3db72 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -2413,7 +2413,7 @@ thread_shutdown(PyObject *self, PyObject *args)
         struct llist_node *node;
         llist_for_each_safe(node, &state->shutdown_handles) {
             ThreadHandle *cur = llist_data(node, ThreadHandle, shutdown_node);
-            if (cur->ident != ident) {
+            if (ThreadHandle_ident(cur) != ident) {
                 ThreadHandle_incref(cur);
                 handle = cur;
                 break;