From b1fd038d43ee5bf7a3e8a5a6954a151bd9468fce Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Mon, 9 Mar 2020 21:51:39 +0100 Subject: [PATCH] bpo-39877: take_gil() checks tstate_must_exit() twice take_gil() now also checks tstate_must_exit() after acquiring the GIL: exit the thread if Py_Finalize() has been called. --- Python/ceval_gil.h | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/Python/ceval_gil.h b/Python/ceval_gil.h index 03f04b93e0a329..9c051ae57b03bc 100644 --- a/Python/ceval_gil.h +++ b/Python/ceval_gil.h @@ -213,8 +213,13 @@ take_gil(PyThreadState *tstate) assert(tstate != NULL); - /* Check if we should make a quick exit. */ if (tstate_must_exit(tstate)) { + /* bpo-39877: If Py_Finalize() has been called and tstate is not the + thread which called Py_Finalize(), exit immediately the thread. + + This code path can be reached by a daemon thread after Py_Finalize() + completes. In this case, tstate is a dangling pointer: points to + PyThreadState freed memory. */ PyThread_exit_thread(); } @@ -282,6 +287,18 @@ take_gil(PyThreadState *tstate) MUTEX_UNLOCK(gil->mutex); + if (tstate_must_exit(tstate)) { + /* bpo-36475: If Py_Finalize() has been called and tstate is not + the thread which called Py_Finalize(), exit immediately the + thread. + + This code path can be reached by a daemon thread which was waiting + in take_gil() while the main thread called + wait_for_thread_shutdown() from Py_Finalize(). */ + drop_gil(ceval, tstate); + PyThread_exit_thread(); + } + errno = err; }