I sucessfully installed cowiki and was using it for a week and now when I try to use it I keep getting this error in the httpd logs:

[notice] child pid 7778 exit signal Segmentation fault (11)

Of course the pid keeps changing on each request. I am running RHEL4 with apache2, php5 and mysql4.1. A little more perusal of the httpd error logs revealed this error (immediately after which I see those segmentation faults):

*** glibc detected *** corrupted double-linked list: 0x08a4de08 ***

A search revealed that apparently MPM in apache2 might be the cultprit. And here is my MPM configuration:

<IfModule prefork.c>
StartServers       8
MinSpareServers    5
MaxSpareServers   20
ServerLimit      256
MaxClients       256
MaxRequestsPerChild  4000

<IfModule worker.c>
StartServers         2
MaxClients         150
MinSpareThreads     25
MaxSpareThreads     75
ThreadsPerChild     25
MaxRequestsPerChild  0

I do have other PHP5 applications running on the same server and I am not seeing this problem with those. So I went in to the index.php and commented out the line include_once 'core.base.php'; Sure enough I see a different error -

"PHP Fatal error:  Class 'Logger' not found in /var/www/html/wiki/index.php on line 40"

which indicates that probably there is some code in the includes files that doesn't like MPM? But certainly this doesn't explain why I was able to use it flawlessly for a week. One reason could be up2date. Every week I do patch my system with the latest bug and security fixes that RHN releases. And the latest that I could see was kernel-util package. I don't know if that caused an issue? But I can guarantee that none of the apache or php packages were updated within the last week. Any ideas?