Bug report
Bug description:
During enumerate.reduce there is an unprotected read of ->en_index
| result = Py_BuildValue("O(On)", Py_TYPE(en), en->en_sit, en->en_index); |
TSAN flagged this, likely not a high impact python issue though
import itertools
import threading
en = enumerate(itertools.count()) # infinite inner iterator: next() never ends
stop = threading.Event()
def advance():
while not stop.is_set():
next(en) # enum_next: atomic write of en_index
def read():
while not stop.is_set():
en.__reduce__() # enum_reduce: plain read of en_index
threads = [threading.Thread(target=advance), threading.Thread(target=read)]
for t in threads:
t.start()
threading.Event().wait(2.0)
stop.set()
for t in threads:
t.join()
SUMMARY: ThreadSanitizer: data race enumobject.c:283 in enum_reduce
CPython versions tested on:
CPython main branch
Operating systems tested on:
macOS