[Zope] zope (with cmf) instance being frequently restarted by signal SIGSEGV(11)

[Richard Ettema]

Hi,

I have a cmf site that has begun restarting frequently and at random 
intervals for no apparent reason. This first occurred about 2 weeks ago 
for about 2-3 days with the instance being restarted every 15 mins at 
worst. This problem disappeared as quickly as it had appeared.

2-3 days  ago this same problem reappeared but with the site sometimes 
being restarted 10 times in a 15 minute period. I can find no sequence 
of url calls or any common reason for this to be occurring. The only 
thing I could find was the following entry appearing in the event log 
matching the times I have witnessed the instance restarting via top.

ERROR(200) zdaemon Process 25606 terminated by signal SIGSEGV(11)

The only changes that have occurred around the time of this first 
problem turning up was (other than normal site operation with 
members/items being add/deleted):
-the cpu and memory being upgraded. This was returned to the original 
memory and cpu state to make sure this wasn't the cause. These have been 
swapped in/out with no change so it looks like it is just coincidence.
-some site zope images were modified to set the 'precondition' attr to 
call a python script to set response headers for caching of images in 
apache... This hasn't been undone as the data.fs has since been packed. 
Is there any way this could be related???

There is no obvious signs of anything malicious going on, but this is 
always a possibility I guess? What to check for?

As this has basically brought the site to its knees with proxy errors 
displayed more often than not, has anyone got suggestions on what to 
look for. possibilities (however remote) as I am pretty desperate to get 
this fixed. If there is a simple explanation, what could cause it to 
start out of the blue?

The only possible answer I have come up with while searching is about 
the thread stack size being to small. And having to recompile python 
with this set to a larger figure. Is this related to the problem I am 
having, and is there an easy way to check if this is the case for the 
version I have running? If this is what I need to do, is there a good 
link for details on what needs to be done and how to do it?

CMF: 1.4.2
Zope: (unreleased version, python 2.1.3, linux2)
Python:  2.1.3 (#1, Sep 7 2002, 15:29:56) [GCC 2.95.4 20011002 (Debian 
prerelease)]

Thank you for all your help on this as I am lost at what steps to take next.
Thanks,
Richard.