dovecot - Feb 2013 - Dovecot-2.1.14 - pop3 processes always hangs forever

Hello,

I'm currently experimenting with the 2.1.x series and am facing a behavior I
can't explain; I must be doing something wrong and probably miss the
obvious... ;-)

This is a very basic build on Mac OS X 10.8.2:

	./configure --prefix=/_COD/dovecot-2.1.14 --sysconfdir=/_ETC
--localstatedir=/_VAR --with-sqlite --with-ldap=yes

(Yes, I know, a strange layout, yet very convenient for testing various things
here.)

Dovecot's configuration is very basic too:

	# 2.1.14: /_ETC/dovecot/dovecot.conf
	# OS: Darwin 12.2.1 x86_64  
	auth_verbose = yes
	disable_plaintext_auth = no
	mail_debug = yes
	mail_location = mbox:~/mboxes:INBOX=~/mboxes/inbox
	passdb {
	  args = /_ETC/dovecot/db.conf
	  driver = sql
	}
	ssl = no
	userdb {
	  driver = prefetch
	}

It is started from launchd with the -F flag.

Two users are defined in the database, user1 (100002/100002) and user2
(100003/100003), with "virtual" uids/gids.

Connecting for the first time as user1 through imap:

	$ telnet 127.0.0.1 143
	Trying 127.0.0.1...
	Connected to localhost.
	Escape character is '^]'.
	* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE
AUTH=PLAIN] Dovecot ready.
	a login user1 pass1
	a OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT
SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND
UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC
ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS SPECIAL-USE] Logged in
	b logout
	* BYE Logging out
	b OK Logout completed.
	Connection closed by foreign host.

In mail.log:

	dovecot[2997]: imap-login: Login: user=<user1>, method=PLAIN,
rip=127.0.0.1, lip=127.0.0.1, mpid=3006, secured,
session=<EOWWzjbVxQB/AAAB>
	dovecot[2997]: imap(user1): Debug: Effective uid=100002, gid=100002,
home=/_Data/Mailstores/100002
	dovecot[2997]: imap(user1): Debug: Home dir not found: /_Data/Mailstores/100002
	dovecot[2997]: imap(user1): Debug: fs: root=/_Data/Mailstores/100002/mboxes,
index=, control=, inbox=/_Data/Mailstores/100002/mboxes/inbox, alt
dovecot[2997]: imap(user1): Debug: Namespace : /_Data/Mailstores/100002/mboxes
doesn't exist yet, using default permissions
	dovecot[2997]: imap(user1): Debug: Namespace : Using permissions from
/_Data/Mailstores/100002/mboxes: mode=0700 gid=-1
	dovecot[2997]: imap(user1): Disconnected: Logged out in=8 out=362

While logged in (ie after the login and before the logout), "doveadm
who" shows:

	username # proto (pids) (ips)
	user1    1 imap  (3093) (127.0.0.1)

So far, so good.

Now, let's connect as user2 for the first time, through pop:

	$ telnet 127.0.0.1 110
	Trying 127.0.0.1...
	Connected to localhost.
	Escape character is '^]'.
	+OK Dovecot ready.
	user user2
	+OK
	pass pass2

and the session hangs forever.

This is written in the log:

	dovecot[2997]: pop3-login: Login: user=<user2>, method=PLAIN,
rip=127.0.0.1, lip=127.0.0.1, mpid=3113, secured,
session=<GTOlMjfV3gB/AAAB>
	dovecot[2997]: pop3(user2): Debug: Effective uid=100003, gid=100003,
home=/_Data/Mailstores/100003
	dovecot[2997]: pop3(user2): Debug: Home dir not found: /_Data/Mailstores/100003
	dovecot[2997]: pop3(user2): Debug: fs: root=/_Data/Mailstores/100003/mboxes,
index=, control=, inbox=/_Data/Mailstores/100003/mboxes/inbox, alt
dovecot[2997]: pop3(user2): Debug: Namespace : /_Data/Mailstores/100003/mboxes
doesn't exist yet, using default permissions
	dovecot[2997]: pop3(user2): Debug: Namespace : Using permissions from
/_Data/Mailstores/100003/mboxes: mode=0700 gid=-1
	dovecot[2997]: pop3(user2): Debug: Namespace :
/_Data/Mailstores/100003/mboxes/inbox doesn't exist yet, using default
permissions
	dovecot[2997]: pop3(user2): Debug: Namespace : Using permissions from
/_Data/Mailstores/100003/mboxes: mode=0700 gid=-1
	dovecot[2997]: pop3(user2): Debug: Namespace :
/_Data/Mailstores/100003/mboxes/inbox doesn't exist yet, using default
permissions
	dovecot[2997]: pop3(user2): Debug: Namespace : Using permissions from
/_Data/Mailstores/100003/mboxes: mode=0700 gid=-1

while "doveadm who" pretends nobody is connected:

	username # proto (pids) (ips)

To get rid of the pop3 process, I have to send it a KILL signal: no other way.
But this is noticed by the master process:

	dovecot[2997]: pop3(user2): Fatal: master: service(pop3): child 3113 killed
with signal 9

Note that it is possible to connect afterwards as user2 through imap.
On the other hand, trying to connect as user1 or user2 through pop always hangs.

TIA,
Axel