Aug 29 09:07:35 cliff dovecot: child 22484 (imap) killed with signal 11 Aug 29 09:07:36 cliff dovecot: child 22488 (imap) killed with signal 11
I don't see any other errors in the logs around those messages.
A co-worker reported to me an error when attempting to copy a message to the "Trash" folder. Squirrelmail reported this:
ERROR : Connection dropped by imap-server. Query: COPY 243 "Trash"
I asked him to reproduce this while watching the logs. As soon as he deleted the message (and squirrelmail attempted to move it to the "Trash" folder) I saw one of the above entries.
This is the message in question: http://cliff.mcad.edu/dovecot_bad_message.txt
It seemed to be happening with other messages, too, but that's the only one I identified absolutely.
I dropped back to 1.0-stable and the segfaults stopped and IMAP became speedy again.
-Ben