[Python-Dev] Core dump in garbage collection: _PyGC_Insert???

Tim Peters tim_one@email.msn.com
Mon, 10 Jul 2000 22:00:47 -0400


[Peter Schneider-Kamp]
> I wouldn't bet my life on it, but I don't think the GC code is
> responsible.

[Neil Schemenauer]
> Its hard to say.

I'll second that <wink>.

> The GC code will probably pick up on a lot of problems because it touches
> many objects.  On the other hand, it could be my bug.  I'm prettly
> limited here as my computer is somewhere between Calgary and
> Reston as I type this.  I will try to find the problem though.

I also doubt it's gc's fault:  the recent patches to the gc code were
absolutely vanilla, this all worked fine (at least for me) yesterday, and
it's failing for multiple people on multiple platforms today.  (BTW, Barry,
your core.py does not fail under my Windows build.)  I haven't had more time
tonight to look at it, though, and won't tomorrow either.  "Somehow or
other" the list of objects it's crawling over is totally hosed (length 3,
first one is a legit string object, last two seemingly random trash).

If I remembered how to do this with CVS, I'd just do a mindless binary
search over the last day's patches, rebuilding until the problem goes away
...

OK, if I back out *only* Jeremy's very recent patch to stringobject.c:

http://www.python.org/pipermail/python-checkins/2000-July/006424.html

all my Windows gc failures go away.  I picked on that patch because it's the
only non-trivial patch that's gone in recently to a popular part of the
code.  Jeremy, want to double-check your refcounts <wink -- but it smells
like an extra decref>?

suggestive-but-not-yet-proven-ly y'rs  - tim