STINNER Victor <vstin...@python.org> added the comment:
> (as noted above) make dealloc() for singletons a noop I expect issues with negative reference count value. As you wrote, it triggers a fatal error when Python is built in release mode. > make the initial refcount sufficiently large such that it is unlikely to reach 0 even with races Py_None is heavily used. If the reference count is updated by multiple threads with no lock to protect it, there is a significant risk that value zero will be reached soon or later. -- In the Linux kernel, they started to special type for reference counters, to reduce the risk of vulnerability on reference counter underflow or overflow: * "reference-count protection" for kernel hardening: refcount_t type * https://lwn.net/Articles/728675/ * https://lwn.net/Articles/706498/ The kernel already used atomic_t type. But the issue here is about bugs, since no program is perfect, even the Linux kernel. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue39511> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
