From: Bogdan Romanyuk <65823030+wrongnull@users.noreply.github.com>
Date: Thu, 6 Feb 2025 20:35:37 +0000 (+0300)
Subject: gh-117657: Fix data race in `new_reference` for free threaded build (gh-129665)
X-Git-Tag: v3.14.0a5~80
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=365cf5fc23835fa6dc8608396109085f31d2d5f0;p=thirdparty%2FPython%2Fcpython.git

gh-117657: Fix data race in `new_reference` for free threaded build (gh-129665)
---

diff --git a/Objects/object.c b/Objects/object.c
index fdff16138201..f3c7fa6d906a 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -2485,13 +2485,20 @@ new_reference(PyObject *op)
     op->ob_refcnt = 1;
 #endif
 #else
-    op->ob_tid = _Py_ThreadId();
     op->ob_flags = 0;
     op->ob_mutex = (PyMutex){ 0 };
+#ifdef _Py_THREAD_SANITIZER
+    _Py_atomic_store_uintptr_relaxed(&op->ob_tid, _Py_ThreadId());
+    _Py_atomic_store_uint8_relaxed(&op->ob_gc_bits, 0);
+    _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, 1);
+    _Py_atomic_store_ssize_relaxed(&op->ob_ref_shared, 0);
+#else
+    op->ob_tid = _Py_ThreadId();
     op->ob_gc_bits = 0;
     op->ob_ref_local = 1;
     op->ob_ref_shared = 0;
 #endif
+#endif
 #ifdef Py_TRACE_REFS
     _Py_AddToAllObjects(op);
 #endif
diff --git a/Tools/tsan/suppressions_free_threading.txt b/Tools/tsan/suppressions_free_threading.txt
index e5eb665ae212..b25b3700b356 100644
--- a/Tools/tsan/suppressions_free_threading.txt
+++ b/Tools/tsan/suppressions_free_threading.txt
@@ -22,7 +22,6 @@ race:free_threadstate
 # These warnings trigger directly in a CPython function.
 
 race_top:assign_version_tag
-race_top:new_reference
 race_top:_multiprocessing_SemLock_acquire_impl
 race_top:list_get_item_ref
 race_top:_Py_slot_tp_getattr_hook