[Zope] Zope 2.5.0, thread stack issues

Geoff Gerrietts geoff@gerrietts.net
Thu, 9 May 2002 13:48:06 -0700


Quoting Geoff Gerrietts (geoff@gerrietts.net):
> Under the latest incarnation, I get a system hang so brutal that ps
> quits responding and the system hasta be hard-booted. Yum. :)
> 
> I've impressed our sysadmin. ;) I'll let everyone know what I find
> out....

In keeping with my promise, an update.

The application in question relies on ILU for communication with the
backend services (including authentication).

The problem I was experiencing was a consequence of a bug in ILU,
solved by our original team but not documented in any way. In other
words, it was, as many suspected, a problem in a third-party
extension. The 2MB stack space reserved by Linux is in fact plenty for
any use case I've come across.

That it did not appear in independent testing of the third-party
extension was an artifact of the test design. When used for
authentication, the application writers used the buggy feature in such
a way as to exercise the bug, and this feature was used elsewhere only
in a relatively innocuous fashion. To the uninitiated (me), it wasn't
even obvious that there was a difference.

As a side note, debugging threaded applications under Linux is
somewhere between totally useless and extremely annoying. The core
that gets dumped is almost never from the thread that raised the
signal (if in fact it ever is). If you can force things into a single
thread and make them break, you'll be much happier for the effort.

Thanks, everyone, for all your insight and assistance.

--G.

-- 
Geoff Gerrietts             "Don't get suckered in by the comments-- 
<geoff at gerrietts net>     they can be terribly misleading.
www.gerrietts.net/geoff/     Debug only code." --Dave Storer