[Dovecot] Dovecot imap processes pinning CPU

[David Rosenstrauch]

In recent days, dovecot's "imap" processes keep getting stuck.  Each 
time I check my server (running dovecot 1.1.7) there's a bunch of "imap" 
processes (sometimes 2 of them, sometimes 4, sometimes 6) that are using 
all of the box's CPU.

And worse, there's no way to kill the processes either (neither kill -15 
or kill -9 works), which means that I wind up having to reboot the box 
every time this happens.  REALLY irritating.

I don't normally even *see* the imap processes in htop, as I think 
they're pretty short lived.  And I'm not sure what they're looping 
trying to do.  My debugging skills on Linux are a bit weak, and so I 
don't know how to look at the process and see what it's doing.

Also, not sure what's changed on my system to cause this, as this is
definitely a recent problem.  Maybe the upgrade to Thunderbird 2.0.0.18
(since I usually use T'Bird to access my email).  I don't seem to run 
into this problem when I use Squirrelmail.

Anyone have any idea what the problem might be?  Or, if not, then 
suggestions on how I might be able to debug the situation myself?

TIA,

DR