New submission from Maxime Belanger <m...@dropbox.com>: Through the use of various Python packages (such as `pyobjc`), it is possible for a deadlock to occur due to how `_scproxy.c` calls `SCDynamicStoreCopyProxies`.
In more recent versions of macOS (10.7+), this function can block on acquiring a lock deep inside `NSUserPreferences`. As `pyobjc` allows Python-wrapped `NSString`s to be stored in `CFPreferences`, it is thus possible for one thread to hold the `CFPreferences` lock and block on the GIL while another thread holds the GIL and blocks on the `CFPreferences` lock. We've observed this on a significant number of macOS devices before fixing ourselves by wrapping the calls to `SCDynamicStoreCopyProxies` with `Py_BEGIN/END_ALLOW_THREADS`. ---------- components: macOS messages: 305247 nosy: Maxime Belanger, ned.deily, ronaldoussoren priority: normal severity: normal status: open title: `_scproxy` calls SystemConfiguration functions in a way that can cause deadlocks type: crash versions: Python 2.7, Python 3.5, Python 3.6, Python 3.7 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue31903> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
