Issue #14432: Generator now clears the borrowed reference to the thread state
Fix a crash when a generator is created in a C thread that is destroyed while
the generator is still used. The issue was that a generator contains a frame,
and the frame kept a reference to the Python state of the destroyed C thread.
The crash occurs when a trace function is setup.
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 4e7d47d..e4885d1 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -1687,6 +1687,96 @@
Py_RETURN_NONE;
}
+#ifdef WITH_THREAD
+typedef struct {
+ PyThread_type_lock start_event;
+ PyThread_type_lock exit_event;
+ PyObject *callback;
+} test_c_thread_t;
+
+static void
+temporary_c_thread(void *data)
+{
+ test_c_thread_t *test_c_thread = data;
+ PyGILState_STATE state;
+ PyObject *res;
+
+ PyThread_release_lock(test_c_thread->start_event);
+
+ /* Allocate a Python thread state for this thread */
+ state = PyGILState_Ensure();
+
+ res = PyObject_CallFunction(test_c_thread->callback, "", NULL);
+ Py_CLEAR(test_c_thread->callback);
+
+ if (res == NULL) {
+ PyErr_Print();
+ }
+ else {
+ Py_DECREF(res);
+ }
+
+ /* Destroy the Python thread state for this thread */
+ PyGILState_Release(state);
+
+ PyThread_release_lock(test_c_thread->exit_event);
+
+ PyThread_exit_thread();
+}
+
+static PyObject *
+call_in_temporary_c_thread(PyObject *self, PyObject *callback)
+{
+ PyObject *res = NULL;
+ test_c_thread_t test_c_thread;
+ long thread;
+
+ PyEval_InitThreads();
+
+ test_c_thread.start_event = PyThread_allocate_lock();
+ test_c_thread.exit_event = PyThread_allocate_lock();
+ test_c_thread.callback = NULL;
+ if (!test_c_thread.start_event || !test_c_thread.exit_event) {
+ PyErr_SetString(PyExc_RuntimeError, "could not allocate lock");
+ goto exit;
+ }
+
+ Py_INCREF(callback);
+ test_c_thread.callback = callback;
+
+ PyThread_acquire_lock(test_c_thread.start_event, 1);
+ PyThread_acquire_lock(test_c_thread.exit_event, 1);
+
+ thread = PyThread_start_new_thread(temporary_c_thread, &test_c_thread);
+ if (thread == -1) {
+ PyErr_SetString(PyExc_RuntimeError, "unable to start the thread");
+ PyThread_release_lock(test_c_thread.start_event);
+ PyThread_release_lock(test_c_thread.exit_event);
+ goto exit;
+ }
+
+ PyThread_acquire_lock(test_c_thread.start_event, 1);
+ PyThread_release_lock(test_c_thread.start_event);
+
+ Py_BEGIN_ALLOW_THREADS
+ PyThread_acquire_lock(test_c_thread.exit_event, 1);
+ PyThread_release_lock(test_c_thread.exit_event);
+ Py_END_ALLOW_THREADS
+
+ Py_INCREF(Py_None);
+ res = Py_None;
+
+exit:
+ Py_CLEAR(test_c_thread.callback);
+ if (test_c_thread.start_event)
+ PyThread_free_lock(test_c_thread.start_event);
+ if (test_c_thread.exit_event)
+ PyThread_free_lock(test_c_thread.exit_event);
+ return res;
+}
+#endif /* WITH_THREAD */
+
+
static PyMethodDef TestMethods[] = {
{"raise_exception", raise_exception, METH_VARARGS},
{"test_config", (PyCFunction)test_config, METH_NOARGS},
@@ -1745,6 +1835,10 @@
{"make_exception_with_doc", (PyCFunction)make_exception_with_doc,
METH_VARARGS | METH_KEYWORDS},
{"sequence_delitem", (PyCFunction)sequence_delitem, METH_VARARGS},
+#ifdef WITH_THREAD
+ {"call_in_temporary_c_thread", call_in_temporary_c_thread, METH_O,
+ PyDoc_STR("set_error_class(error_class) -> None")},
+#endif
{NULL, NULL} /* sentinel */
};