Don't drop the GIL during thread deletion unless the current thread h…

…olds it

Lib/test/test_importlib/test_threaded_import.py

@@ -17,7 +17,7 @@
 from test.support import verbose
 from test.support.import_helper import forget, mock_register_at_fork
 from test.support.os_helper import (TESTFN, unlink, rmtree)
-from test.support import script_helper, threading_helper, requires_gil_enabled
+from test.support import script_helper, threading_helper
 
 threading_helper.requires_working_threading(module=True)
 
@@ -248,9 +248,6 @@ def test_concurrent_futures_circular_import(self):
                           'partial', 'cfimport.py')
         script_helper.assert_python_ok(fn)
 
-    # gh-118727 and gh-118729: pool_in_threads.py may crash in free-threaded
-    # builds, which can hang the Tsan test so temporarily skip it for now.
-    @requires_gil_enabled("gh-118727: test may crash in free-threaded builds")
     def test_multiprocessing_pool_circular_import(self):
         # Regression test for bpo-41567
         fn = os.path.join(os.path.dirname(__file__),

Python/pystate.c

@@ -1831,10 +1831,22 @@ _PyThreadState_DeleteCurrent(PyThreadState *tstate)
     _Py_EnsureTstateNotNULL(tstate);
 #ifdef Py_GIL_DISABLED
     _Py_qsbr_detach(((_PyThreadStateImpl *)tstate)->qsbr);
+    // tstate_delete_common() removes tstate from the tracking used by the
+    // stop-the-world machinery. This means that another thread could enable
+    // the GIL before our call to _PyEval_ReleaseLock(), violating its
+    // assumption that its only called by an attached thread that holds the GIL
+    // if and only if the GIL is enabled. Work around this by deciding if we
+    // need to release the GIL while our thread is still considered for
+    // stop-the-world.
+    int holds_gil = _PyEval_IsGILEnabled(tstate);
+#else
+    int holds_gil = 1;
 #endif
     current_fast_clear(tstate->interp->runtime);
     tstate_delete_common(tstate);
-    _PyEval_ReleaseLock(tstate->interp, NULL);
+    if (holds_gil) {
+        _PyEval_ReleaseLock(tstate->interp, NULL);
+    }
     free_threadstate((_PyThreadStateImpl *)tstate);
 }