Dovecot hangs on all logins including local telnet [closed]
Solution 1:
Running Dovecot with strace reveals that it was being held up by attempting to stat a hanging sshfs mount in a user's home directory. Forcing this unmounted resolves my problem. The user had a sshfs in their crontab, so the reboot post-update caused the immediate issue, not the update itself. I have no clue why it was statting that file. I hate computers.