Message 357170 - Python tracker

Message357170

Author	pconnell
Recipients	Johan Dahlin, db3l, emilyemorehouse, eric.snow, koobs, nascheme, ncoghlan, pconnell, pmpp, serhiy.storchaka, shprotx, steve.dower, vstinner, yselivanov
Date	2019-11-21.13:55:57
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1574344558.04.0.161892905653.issue33608@roundup.psfhosted.org>
In-reply-to

Content
Just to summarise, I'm fairly sure this is exactly what Victor saw: a daemon thread attempts to reacquire the GIL via Py_END_ALLOW_THREADS after interpreter finalisation. Obviously the threadstate pointer held by the thread is then invalid...so we crash. So I see basically two options: 1. Don't (always) free threadstate structures in Py_Finalize, and figure out a way to avoid leaking them (if Python is re-initialized in the same process). 2. Ban this behaviour entirely, e.g. have Py_Finalize fail if there are live threads with threadstate objects. The discussion so far assumes that we should support this, i.e. #1. Any thoughts on that? (I'll have a think about whether this is actually doable!)

Content

Just to summarise, I'm fairly sure this is exactly what Victor saw: a daemon thread attempts to reacquire the GIL via Py_END_ALLOW_THREADS after interpreter finalisation. Obviously the threadstate pointer held by the thread is then invalid...so we crash.

So I see basically two options:

1. Don't (always) free threadstate structures in Py_Finalize, and figure out a way to avoid leaking them (if Python is re-initialized in the same process).

2. Ban this behaviour entirely, e.g. have Py_Finalize fail if there are live threads with threadstate objects.

The discussion so far assumes that we should support this, i.e. #1. Any thoughts on that? (I'll have a think about whether this is actually doable!)

History
Date	User	Action	Args
2019-11-21 13:55:58	pconnell	set	recipients: + pconnell, nascheme, db3l, ncoghlan, vstinner, pmpp, eric.snow, serhiy.storchaka, yselivanov, koobs, steve.dower, emilyemorehouse, Johan Dahlin, shprotx
2019-11-21 13:55:58	pconnell	set	messageid: <1574344558.04.0.161892905653.issue33608@roundup.psfhosted.org>
2019-11-21 13:55:58	pconnell	link	issue33608 messages
2019-11-21 13:55:57	pconnell	create