If you are using systemd, create /etc/systemd/system/dovecot.service.d/limits.conf and put

[Service]

LimitCORE=infinity

and run

systemctl daemon-reload

systemctl restart dovecot

---

Aki Tuomi

Dovecot oy

-------- Original message --------

From: Simone Lazzaris <s.lazzaris@interactive.eu>

Date: 18/09/2018 15:01 (GMT+02:00)

To: Timo Sirainen <tss@iki.fi>

Cc: dovecot@dovecot.org

Subject: Re: Auth process sometimes stop responding after upgrade

Alas, I've set fs.suid_dumpable to 2 but the core is not dumped. So far I've checked:

- ulimit -c unlimited, done

- /proc/sys/kernel/core_pattern is set to /var/tmp/core.%p

- /var/tmp is chmod 1777

- daemon is not chrooted

- sysctl -w fs.suid_dumpable=2

- dir /var/tmp is empty and filesystem has 2GB free

This is the logfile:

Sep 18 13:54:22 imap-front4 dovecot: director: doveadm: Host 192.168.1.145 changed down (vhost_count=100 last_updown_change=0)

Sep 18 13:54:52 imap-front4 dovecot: director: doveadm: Host 192.168.1.145 changed up (vhost_count=100 last_updown_change=1537271662)

Sep 18 13:54:52 imap-front4 dovecot: director: Panic: file doveadm-connection.c: line 1097 (doveadm_connection_deinit): assertion failed: (conn->to_ring_sync_abort == NULL)

Sep 18 13:54:52 imap-front4 dovecot: director: Error: Raw backtrace: /usr/local/lib/dovecot/libdovecot.so.0(+0xa15be) [0xb76fa5be] -> /usr/local/lib/dovecot/libdovecot.so.0(+0xa1641) [0xb76fa641] -> /usr/local/lib/dovecot/libdovecot.so.0(i_fatal+0) [0xb768035e] -> dovecot/director() [0x80574f7] -> dovecot/director() [0x8057f03] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x6b) [0xb77133db] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0xfe) [0xb7714e1e] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x46) [0xb7713496] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_run+0x48) [0xb7713658] -> /usr/local/lib/dovecot/libdovecot.so.0(master_service_run+0x2e) [0xb768c45e] -> dovecot/director(main+0x49e) [0x804cf5e] -> /lib/i386-linux-gnu/i686/cmov/libc.so.6(__libc_start_main+0xe6) [0xb7501e46] -> dovecot/director() [0x804d081]

Sep 18 13:54:52 imap-front4 dovecot: director: Fatal: master: service(director): child 8059 killed with signal 6 (core not dumped)

Sep 18 13:54:52 imap-front4 dovecot: director: Connecting to 212.183.164.161:9090 (as 212.183.164.164): Initial connection

Sep 18 13:54:52 imap-front4 dovecot: director: Incoming connection from director 212.183.164.163/in

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.142 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.143 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.144 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.145 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.216 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.217 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.218 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Host 192.168.1.219 vhost count changed from 100 to 100

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.161:9090/out): Handshake finished in 0.001 secs (bytes in=61, bytes out=791, 0+0 USERs received, last input 0.000 s ago, last output 0.001 s ago, connected 0.001 s ago, 408 peak output buffer size, 0.000 CPU secs since connected)

Sep 18 13:54:52 imap-front4 dovecot: director: director(212.183.164.163/in): Handshake finished in 0.006 secs (bytes in=111411, bytes out=56, 2940+0 USERs received, last input 0.000 s ago, last output 0.006 s ago, connected 0.006 s ago, 0 peak output buffer size, 0.004 CPU secs since connected)

I can confirm that I can trigger the issue having one of the backends flapping down/up.