slapd hangs upon performing modification of cn=config

[Patrick Hemmer]

I have a database which was working fine, but now whenever I go to 
perform any sort of modification on the database, the modification just 
hangs. No error, no timeout, just sits there. However while that first 
modification is hung, I can perform modifications of another database 
(other than cn=config) and they work just fine. I can even do further 
searches against cn=config while the modification is still hung.
Also when I run slapd in the foreground, and then send it a SIGINT, it 
says "slapd shutdown: waiting for X operations/tasks to finish" and 
never ends. I end up having to SIGKILL it.

The database is part of a MMR group of servers I was building, but I 
shut down all the other servers to troubleshoot the issue (it makes no 
difference whether the other servers are up or down, and they all 
exhibit the same problem).

Where should I start looking to figure out whats going on (the specific 
operation/task thats hanging)? I can run slapd in debug mode with '-1', 
but theres a ton of info, and I dont know whats relevant, or which debug 
mode I should use other than '-1'.

Thanks

-Patrick