general protection fault and howto capture core dump

[Miguel DeAvila]

We're having fairly regular outages in our memcache cluster ...
the memcached process is exiting abnormally.

The only log entry we can see is via dmesg,

        memcached[3020] general protection rip:407ed9 rsp:7fff7cdeb238 error:0

Anyone seen this?

We also have not had any luck getting a core dump. We're running
CentOS release 5 (Final).

I think we've taken the necessary steps to encourage a core dump,

[root at memcache04 ~]# cat /proc/sys/kernel/core_pattern
core

[root at memcache04 ~]# cat /proc/sys/kernel/core_uses_pid
1

My one suspicion is that the current working dir for the memcached process
is /root, but the process is running as the www user, so it does not have write
permission.

Any tips?

thanks,

Miguel