New submission from Ferringb <ferri...@gmail.com>: During Py_Finalize (pythonrun.c), it does the following: 1) suppress signal handling PyOs_FiniInterupts 2) clear caches 3) force gc collection; first for objects, then via wiping modules.
The problem is that for unix OSs, Modules/signal.c's PyOs_FiniInterrupts leaves itself in a state where its internal Handlers are effectively reset to NULL, except the various functions don't properly handle that scenario. Attached is a test case demonstrating it; it segfaults on every python version I've tested (2.4->3.2; haven't tried 3.3). Since this *only* occurs during the final gc sweep when modules are destroyed, its a bit of a pain in the ass to detect that we're in that scenario, and that we must not touch signal.getsignal lest it segfault the interp. That said, def _SignalModuleUsable(): try: signal.signal(signal.SIGUSR1, signal.signal(signal.SIGUSR1, some_handler)) return True except (TypeError, AttributeError, SystemError): # we were invoked in a module cleanup context. return False does manage to poke the api just right so that it can be detected w/out segfaulting the interp. Finally, note that while folks could point at __del__... its not really at fault. Doing a proper weakref.ref finalizer can trigger the same- the fault is signal.c's PyOs_FiniInterrupts leaving the signal module in a bad state. For the testcase, I used __del__ just because it was quicker/less code to do so. ---------- components: Interpreter Core files: test.py messages: 154758 nosy: ferringb priority: normal severity: normal status: open title: PyOS_FiniInterupts leaves signal.getsignal segfaulty type: crash versions: Python 2.6, Python 2.7, Python 3.1, Python 3.2 Added file: http://bugs.python.org/file24703/test.py _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue14173> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
