dovecot - Feb 2014 - Dovecot stopped with "master: Fatal: kevent(): Invalid argument"

Hi,

after more than 20 days uptime, Dovecot stopped with the following logged in
/var/log/messages:

- master: Fatal: kevent(): Invalid argument


dovecot -n:

# 2.2.10: /usr/local/etc/dovecot/dovecot.conf
# OS: FreeBSD 9.2-RELEASE-p3 amd64
auth_default_realm = xxx.com.ua
auth_mechanisms = plain login
default_client_limit = 3000
dict {
  quotadict = mysql:/usr/local/etc/dovecot/dovecot-dict-quota.conf
}
disable_plaintext_auth = no
doveadm_password = xxx
doveadm_port = xxx
first_valid_gid = 6
first_valid_uid = 26
listen = 10.xx.xx.xx 10.xx.xx.xx
login_log_format_elements = user=<%u> method=%m rip=%r %c
mail_location = mdbox:~/mdbox
mail_plugins = quota mail_log notify replication
mail_privileged_group = mail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character
vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy
include variables body enotify environment mailbox date ihave
mdbox_rotate_interval = 2 weeks
mdbox_rotate_size = 25 M
passdb {
  args = /usr/local/etc/dovecot/dovecot-mysql.conf
  driver = sql
}
plugin {
  mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename
  mail_log_fields = uid box msgid size
  mail_replica = tcp:xxx.xxx.com.ua
  quota = dict:user::proxy::quotadict
  quota_warning = storage=95%% quota-warning 95 %u
  quota_warning2 = storage=85%% quota-warning 85 %u
  replication_full_sync_interval = 12 hours
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
protocols = imap pop3 lmtp sieve
service aggregator {
  fifo_listener replication-notify-fifo {
    user = mailnull
  }
  unix_listener replication-notify {
    user = mailnull
  }
}
service dict {
  unix_listener dict {
    group = mail
    mode = 0600
    user = mailnull
  }
}
service doveadm {
  inet_listener {
    port = xxx
  }
}
service imap-login {
  client_limit = 3000
  process_min_avail = 8
  service_count = 0
  vsz_limit = 256 M
}
service lmtp {
  executable = lmtp -L
  group = mail
  process_min_avail = 5
  unix_listener lmtp {
    mode = 0666
  }
  user = mailnull
}
service managesieve-login {
  process_min_avail = 2
  service_count = 1
}
service managesieve {
  process_limit = 128
}
service pop3-login {
  process_limit = 1024
  process_min_avail = 8
  service_count = 1
}
service quota-warning {
  executable = script /usr/local/bin/quota-warning.sh
  group = mail
  unix_listener quota-warning {
    group = mail
    mode = 0600
    user = mailnull
  }
  user = mailnull
}
service replicator {
  process_min_avail = 1
  unix_listener replicator-doveadm {
    mode = 0600
    user = mailnull
  }
}
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key = </etc/ssl/private/dovecot.pem
userdb {
  args = /usr/local/etc/dovecot/dovecot-mysql.conf
  driver = sql
}
valid_chroot_dirs = /var/mail
verbose_proctitle = yes
protocol imap {
  imap_client_workarounds = delay-newmail tb-extra-mailbox-sep tb-lsub-flags
  mail_plugins = quota mail_log notify replication imap_quota
}
protocol pop3 {
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
  pop3_enable_last = yes
  pop3_fast_size_lookups = yes
  pop3_no_flag_updates = yes
  pop3_uidl_format = %08Xu%08Xv
}
protocol lda {
  info_log_path = /var/log/dovecot/lda.log
  log_path = /var/log/dovecot/lda_error.log
  postmaster_address = postmaster at xxx.com.ua
  quota_full_tempfail = no
  sendmail_path = /usr/local/sbin/exim
}
protocol lmtp {
  info_log_path = /var/log/dovecot/deliver.log
  log_path = /var/log/dovecot/error_lmtp.log
  postmaster_address = postmaster at xxx.com.ua
  quota_full_tempfail = no
  sendmail_path = /usr/local/sbin/exim
}


Best regards,
Mike