Hi,

Auth process is not constantly being shutdown and/or restarted and Dovecot is used for SMTP authentication (Postfix).

Checked few servers logs, they are running v2.3.3, for example latest
(some day none, some day a lot, some day few) logs:

Nov 25 18:48:11 server1 dovecot: auth: Warning: Event 0x2b79250f15f0
leaked (parent=(nil)): auth-client-connection.c:338

I suppose these are happening because of:

dovecot: auth: Warning: auth client 0 disconnected with 1 pending
requests: EOF: 12 Time(s)

Which probably happens when Postfix disconnects from Dovecot before the authentication has finished.

I can reproduce these if I set up PAM authentication and then do:

doveadm auth test testuser wrongpass

Repeat the above a few times. Each time logs:

Nov 26 13:36:13.588354 auth: Warning: auth client 0 disconnected with 1 pending requests: EOF

Then stop Dovecot (or auth process at least):

Nov 26 13:36:23.403778 auth: Warning: Event 0x561565277db0 leaked (parent=(nil)): auth-client-connection.c:338