Getting a core dump from Varnish 1.1.2

[Nathan Kinkade]

We were having some problems with Varnish on an i386 build of Debian
Etch.  After reading the following ticket I decided to upgrade our
servers to an amd64 build:
http://varnish.projects.linpro.no/ticket/85.

So, on two of the servers we are getting segmentation faults from
Varnish every now and then (not too frequently).  I rebuilt Varnish
following the instructions for debugging at:
http://varnish.projects.linpro.no/wiki/DebuggingVarnish, but Varnish
doesn't seem to be outputting core dump files.  I've got Varnish
running in a screen session and when a child process segfaults, I see
things like this in the terminal:

Child said (2, 13865): <<flunk 8192 4948
>>
Cache child died pid=13865 status=0xb
Clean child
Child cleaned
start child pid 11024
Child said (2, 11024): <<Child starts

... but no core dump (I'm looking in the same directory as where the
_.vsl file is located) and for this test Varnish is running as root.
I also ran "ulimit -C unlimted" in the terminal before launching
varnishd.

Would all this imply that I didn't actually get the debugging
configure options into the build correctly?  The binary says "not
stripped".  I have to admit I'm a bit of a newbie at debugging and
core dumps.

We are running Varnish 1.1.2, but patched to fix this small bug:
http://varnish.projects.linpro.no/ticket/197

$ uname -r
2.6.18-6-amd64

Maybe there's something obvious I'm missing here?

Thanks,

Nathan