New submission from mrc <marco.giu...@posteo.de>:
DataGraham in #django reported a deadlock with a very specific logging configuration. Issue is reproducible from this code: https://github.com/data-graham/wedge. To trigger the deadlock at least one handle must be enable. Note how there there are no loggers using those handlers. (https://github.com/data-graham/wedge/blob/master/wedge/settings.py#L127-L169) The two offending locks causing the deadlock are logging._lock and a lock used by importlib._bootstrap._imp (_PyImport_AcquireLock). TH1> start and complete the logging configuration via dictConfig. An handler is configured but no logger uses it, only a weakref holds it TH2> start logging configuration, acquires logging._lock TH1> import some module, acquiring the import lock TH1> the garbage collector starts and reclaims the unused handled (only a weakref exists) TH1> the weakref callback tries to acquire logging._lock. WAITING TH2> start importing some module, try to acquire import lock. DEADLOCK Attached the traceback of the threads. I could test this with Python3.7 only (and Django 3.0). ---------- components: Library (Lib) files: deadlock_logging.log messages: 367085 nosy: mrc priority: normal severity: normal status: open title: Deadlock in logging.config.dictConfig versions: Python 3.7 Added file: https://bugs.python.org/file49088/deadlock_logging.log _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40371> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
