Multithreaded subinterpreters can be running during finalization · Issue #126016 · python/cpython (original) (raw)
Crash report
What happened?
(Found while investigating a fix for #125920.)
Subinterpreters that are running in a different thread can still be running upon the finalization of the main interpreter, depending on what the thread was doing. Take the following script:
from threading import Thread import _interpreters
def silly(): interp = _interpreters.create() _interpreters.run_string(interp, "import time; time.sleep(100)")
if name == "main": Thread(target=silly).start()
On 3.13 and 3.14, killing the process with CTRL+C results in an assertion failure:
python: Python/pylifecycle.c:2480: finalize_subinterpreters: Assertion `!_PyInterpreterState_IsRunningMain(interp)' failed.
However, if the thread is daemon, then the interpreter fully segfaults:
from threading import Thread import _interpreters
def silly(): interp = _interpreters.create() _interpreters.run_string(interp, "import time; time.sleep(100)")
if name == "main": Thread(target=silly, daemon=True).start()
I'm going to investigate possible fixes.
CPython versions tested on:
3.13, CPython main branch
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
No response