Greets,
I'm using dovecot 2.0.9 (also tried rolling back to 2.0.8 which does the same
- the output below is from 2.0.8), and this problem is imap specific.
The following is a recurring problem with a specific user - as far as we can
tell, other users are working just fine (there are thousands); but I bet there
are others.
In a nutshell: User authenticates OK, then the imap process hangs.
It's almost as if something in the user's inbox is causing the problem, since
if I clear all emails (and cache), then things work fine. The user will then
receive emails OK for some random period (maybe a few days) and be able to
read/write OK via imap, and the problem will re-occur.
The debug output shows nothing untoward:
auth: Debug: auth client connected (pid=20774)
auth: Debug: client in: AUTH1 PLAIN service=imapsecured
lip=127.0.0.1 rip=127.0.0.1 lport=144 rport=41641 resp=
auth: Debug: shadow(username,127.0.0.1): lookup
auth: Debug: client out: OK 1 user=username
auth: Debug: master in: REQUEST 1938161665 20774 1
238230058d076a9af1cd4405244d33ba
auth: Debug: passwd(username,127.0.0.1): lookup
auth: Debug: master out: USER 1938161665 username
system_groups_user=usernameuid=17286 gid=300
home=/home/mailusers/username
imap-login: Info: Login: user=, method=PLAIN, rip=127.0.0.1,
lip=127.0.0.1, mpid=20775, secured
imap(username): Debug: Effective uid=17286, gid=300,
home=/home/mailusers/username
imap(username): Debug: fs: root=/home/mailusers/username/., index=, control=,
inbox=/var/mail/username
Rawlog looks good:
IN:
A002 CAPABILITY
A003 NAMESPACE
C64 EXAMINE ""
A002 STATUS "INBOX" (MESSAGES UNSEEN RECENT)
A003 SELECT "INBOX"
A004 EXPUNGE
A005 SELECT "INBOX"
A006 EXPUNGE
A007 UID SEARCH UNSEEN
A008 UID FETCH 2533:2588 (FLAGS BODY.PEEK[HEADER.FIELDS (RECEIVED)])
OUT:
...
* 15 FETCH (UID 2536 FLAGS () BODY[HEADER.FIELDS (RECEIVED)] {944}
...
* 67 FETCH (UID 2588 FLAGS () BODY[HEADER.FIELDS (RECEIVED)] {945}
...
A008 OK Fetch completed.
It's at this point that nothing happens for a short while and the user gets a
blank screen.
I tried running it through gdb (ie, "Talk IMAP Directly" - as described at
http://dovecot.org/bugreport.html), but that fails with "Cannot find
user-level thread for LWP : generic error", which is probably specific to
our old box/installation.
strace hangs with:
Process 6574 attached - interrupt to quit
gettimeofday({1296472202, 318955}, NULL) = 0
gettimeofday({1296472202, 319073}, NULL) = 0
epoll_wait(0x8, 0x806c4f8, 0x6, 0x1b708d
gdb backtrace gives:
0xb7e2bff9 in epoll_wait () from /lib/tls/libc.so.6
(gdb) bt full
#0 0xb7e2bff9 in epoll_wait () from /lib/tls/libc.so.6
No symbol table info available.
#1 0xb7eed4eb in io_loop_handler_run (ioloop=0x806c390) at ioloop-epoll.c:181
ctx = (struct ioloop_handler_context *) 0x806c4b8
list = (struct io_list *) 0x8082850
io = (struct io_file *) 0x806c4f8
tv = {tv_sec = 1696, tv_usec = 510098}
msecs = 8
ret = -1
i = 0
j = -1208929836
call = 8
#2 0xb7eec249 in io_loop_run (ioloop=0x806c390) at ioloop.c:404
No locals.
#3 0xb7ed8e15 in master_service_run (service=0x806c2e0, callback=0xfffc)
at master-service.c:484
No locals.
#4 0x0805ee75 in main (argc=1, argv=0x806c1d8) at main.c:375
set_roots = {0x8061d80, 0x0}
service_flags = 6
storage_service_flags = MAIL_STORAGE_SERVICE_FLAG_DISALLOW_ROOT
postlogin_socket_path = 0x806c2e0
"\220�\006\bp�\006\b\200�\006\b\b"
username = 0x0
c = -4
(gdb)
lsof shows:
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
imap6574 username cwdDIR9,0 4096 30130787
/home2/home/mailusers/username
imap6574 username rtdDIR3,1 4096 2 /
imap6574 username txtREG9,0 941700 35836003
/home2/local/libexec/dovecot/imap
imap6574 username memREG0,0 0 [heap] (stat:
No such file or directory)
imap6574 username memREG9,0 109568 30130578
/home2/home/mailusers/username/.imap/INBOX/dovecot.index.cache
imap6574 username memREG3,141351 13749135
/lib/tls/libnss_files-2.3.5.so
imap6574 username memREG3,141583 13749137
/lib/tls/libnss_nis-2.3.5.so
imap6574 username memREG3,192501 13749132
/lib/tls/libnsl-2.3.5.so
imap6574 username memREG3,135866 13749133
/lib/tls/libnss_compat-2.3.5.so
imap6574 username memREG3,187827 13749140
/lib/tls/libpthread-2.3.5.so
imap6574 username memREG3,1 1366940 13749126
/lib/tls/libc-2.3.5.so
imap6574 username memREG3,134582 13749142
/lib/tls/librt-2.3.5.so
imap6574 username memREG3,113120 13749129
/lib/tls/libdl-2.3.5.so
imap6574 username memREG9,0173806897709
/home2/home/mailusers/usernam
