[Dovecot] Fatal failure in auth-worker with dovecot-1.1.5

[arvids]

Hello,

after upgrade from dovecot-1.1.3 to dovecot-1.1.5 I am
getting Fatal failures in auth-worker:

Oct 26 14:00:31 host dovecot: auth(default): new auth connection: pid=27526
Oct 26 14:00:31 host dovecot: auth(default): client in: AUTH^I1^IDIGEST-MD5^Iservice=smtp
Oct 26 14:00:31 host dovecot: auth(default): client out: CONT^I1^IcmVhbG09IiIsbm9uY2U9IitTWElHWnJabHFkb0hoa0ttRktLdEE9PSIscW9wPSJhdXRoIixjaGFyc2V0PSJ1dGYtOCIsYWxnb3JpdGhtPSJtZDUtc2VzcyI=
Oct 26 14:00:31 host dovecot: auth(default): client in: CONT<hidden>
Oct 26 14:00:31 host dovecot: auth(default): cache(me): expired
Oct 26 14:00:31 host dovecot: auth-worker(default): sql(me): query: SELECT user, clear as password, home as userdb_home, uid as userdb_uid, gid as userdb_gid, concat('*:storage=',quota_kb,'
:messages=',quota_num) AS userdb_quota_rule,concat('storage=',round(quota_kb*0.90),' /etc/postfix/quotawarn.sh storage 90') AS userdb_quota_warning, concat('messages=',round(quota_num*0.90)
,' /etc/postfix/quotawarn.sh messages 90') AS userdb_quota_warning2 FROM users WHERE user = 'me'
Oct 26 14:00:31 host dovecot: Fatal: auth-worker(default): digest_md5_generate(): username not given
Oct 26 14:00:31 host dovecot: child 24174 (auth-worker) returned error 89 (Fatal failure)
Oct 26 14:00:31 host dovecot: auth(default): worker-server(me): Aborted: Worker process died unexpectedly
Oct 26 14:00:31 host dovecot: auth(default): cache(me): hit: <hidden>^Iuser=me^Iuserdb_home=/var/vmail/me^Iuserdb_uid=95^Iuserdb_gid=95^Iuserdb_quota_rule=*:storage=5000000:messages=50000^I
userdb_quota_warning=storage=4500000 /etc/postfix/quotawarn.sh storage 90^Iuserdb_quota_warning2=messages=45000 /etc/postfix/quotawarn.sh messages 90
Oct 26 14:00:31 host dovecot: auth(default): passdb(me): Fallbacking to expired data from cache
Oct 26 14:00:31 host dovecot: auth(default): client out: CONT^I1^IcnNwYXV0aD03MmIzMDI3NzI5MmI0N2VlZTRiMTdiZmExODhmODE0Zg==
Oct 26 14:00:31 host dovecot: auth(default): client in: CONT<hidden>
Oct 26 14:00:31 host dovecot: auth(default): client out: OK^I1^Iuser=me

There were no such errors with exactly the same config in dovecot-1.1.3.
I can not reproduce it, but it happens quite often and with different clients - 
IMAP and POP3, clients with expired auth data in cache and clients wihout
auth data in cache.

Here is my dovecot  -n output:
# 1.1.5: /usr/local/dovecot/etc/dovecot.conf
base_dir: /var/run/dovecot/
syslog_facility: local7
protocols: pop3 imap
ssl_cert_file: /etc/postfix/host-cert.pem
ssl_key_file: /etc/postfix/host-key.pem
disable_plaintext_auth: no
verbose_ssl: yes
login_dir: /var/run/dovecot/login
login_executable(default): /usr/local/dovecot/libexec/dovecot/imap-login
login_executable(imap): /usr/local/dovecot/libexec/dovecot/imap-login
login_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3-login
login_greeting: Server.
login_process_per_connection: no
login_processes_count: 5
login_max_processes_count: 32
verbose_proctitle: yes
first_valid_uid: 95
first_valid_gid: 95
mail_uid: 95
mail_gid: 95
mail_location: maildir:~/Maildir
mail_debug: yes
fsync_disable: yes
mail_executable(default): /usr/local/dovecot/libexec/dovecot/imap
mail_executable(imap): /usr/local/dovecot/libexec/dovecot/imap
mail_executable(pop3): /usr/local/dovecot/libexec/dovecot/pop3
mail_plugins(default): quota imap_quota
mail_plugins(imap): quota imap_quota
mail_plugins(pop3): quota
mail_plugin_dir(default): /usr/local/dovecot/lib/dovecot/imap
mail_plugin_dir(imap): /usr/local/dovecot/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/local/dovecot/lib/dovecot/pop3
imap_client_workarounds(default): delay-newmail
imap_client_workarounds(imap): delay-newmail
imap_client_workarounds(pop3):
pop3_enable_last(default): no
pop3_enable_last(imap): no
pop3_enable_last(pop3): yes
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
namespace:
  type: private
  separator: .
  inbox: yes
  list: yes
  subscriptions: yes
auth default:
  mechanisms: plain login digest-md5 cram-md5 apop
  cache_size: 1024
  cache_ttl: 600
  cache_negative_ttl: 60
  user: doveauth
  verbose: yes
  debug: yes
  passdb:
    driver: sql
    args: /usr/local/dovecot/etc/dovecot-sql.conf
  userdb:
    driver: prefetch
  userdb:
    driver: sql
    args: /usr/local/dovecot/etc/dovecot-sql.conf
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: postfix
    master:
      path: /var/run/dovecot/auth-master
      mode: 384
      user: vmail
      group: vmail
plugin:
  quota: dict:::proxy:/var/run/dovecot/dict-server:quotadict
dict:
  quotadict: mysql:/usr/local/dovecot/etc/dovecot-sql-dict-quota.conf

Regards, Arvids