completion.so segfaulting - debugging options?

[kba <unixprog@xxxxxxxxxxxxxx>]

hi zsh users,

I have recently been playing a lot with zsh's completion, adding
snippets from different sources and trying a lot of things. Now I do
have a very sophisticated (read: cluttered) completion setup, thank you
very much :-) Amazing software, really.

The problem is that somewhere in all the setopts and zstyles I have
introduced a bug that leads to zsh segfaulting during completion in
certain conditions I can't reproduce properly. I try to complete a path,
the colorized list of possibilities pops up, I press another key and zsh
quits and in /var/log/messages.log a line
> [13365.361881] zsh[20379]: segfault at 0000000c eip b7c83d1d esp bfde47f0 error 6
pops up. But not always and seemingly not always under the (seemingly)
same conditions.

Now I know, that this is no good bug reporting, so I wanted to know if
there are any options/settings I might try to narrow the problem down
myself and find the cause for it. Can the completion process be
traced/logged, a la "at this point we switch to list-mode, at this point
we switch to menu completion, at this point we segfault"?

Thanks a lot for any hint
kba