[Dovecot] fstat(mboxname.lock) failed: Bad file descriptor

[Mark Sapiro]

I have just upgraded from 1.2.beta1 to 1.2.beta2. My configuration is:

[root at sbh16 ~]# dovecot -n
# 1.2.beta2: /usr/local/etc/dovecot.conf
# OS: Linux 2.6.18-8.1.14.el5 i686 CentOS release 5 (Final)
protocols: pop3 pop3s imap imaps
ssl_cert_file: /etc/postfix/sbh16-cert.pem
ssl_key_file: /etc/postfix/sbh16-key.pem
login_dir: /usr/local/var/run/dovecot/login
login_executable(default): /usr/local/libexec/dovecot/imap-login
login_executable(imap): /usr/local/libexec/dovecot/imap-login
login_executable(pop3): /usr/local/libexec/dovecot/pop3-login
mail_privileged_group: mail
mail_location: mbox:~/Mail:INBOX=/var/spool/mail/%u
mbox_write_locks: fcntl dotlock
mail_executable(default): /usr/local/libexec/dovecot/imap
mail_executable(imap): /usr/local/libexec/dovecot/imap
mail_executable(pop3): /usr/local/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/local/lib/dovecot/imap
mail_plugin_dir(imap): /usr/local/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/local/lib/dovecot/pop3
pop3_lock_session(default): no
pop3_lock_session(imap): no
pop3_lock_session(pop3): yes
auth default:
  mechanisms: plain apop login
  worker_max_count: 5
  passdb:
    driver: passwd-file
    args: /usr/local/etc/dovecot.passwd
  passdb:
    driver: pam
  userdb:
    driver: passwd
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: postfix
[root at sbh16 ~]#

This represents one change from the previous config. Previously with
pop3_lock_session = yes, I needed mail_access_group = mail. With the
upgrade to beta2, I changed that to mail_privileged_group = mail as
shown above.

Now, during a session lasting several seconds, I see the following in
maillog:

Mar 15 09:35:51 sbh16 dovecot: pop3-login: Login: user=<mark>,
method=APOP, rip=68.183.193.239, lip=72.52.113.16, TLS
Mar 15 09:36:01 sbh16 dovecot: POP3(mark): fstat(mark.lock) failed: Bad
file descriptor
Mar 15 09:36:04 sbh16 dovecot: POP3(mark): Disconnected: Logged out
top=0/0, retr=1/1919972, del=0/328, size=5381253
Mar 15 09:36:04 sbh16 dovecot: child 9023 (pop3) killed with signal 11
(core dumps disabled)

This does not occur with shorter sessions lasting only a few seconds or
less. The only symptom is the log messages. The client sees nothing
unusual, at least in this case where the session is a retrieval of one
large message. I haven't tried long sessions retrieving multiple
messages.

If I remove pop3_lock_session = yes, the issue does not occur. I don't
think I need it. I put it in a long time ago to attempt to solve a
problem that was actually caused by something else. Since removing it
does seem to avoid this issue, I will leave it out, but I'm reporting
this anyway as it seems there may be some underlying problem.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan