[Dovecot] Panic in version 1.1.6

[Rob Mangiafico]

> We have seen a few of these panics in 1.1.6. It seems to happen when pine is 
> being used and a POP3 check occurs at the same time (but not always), but I'm 
> not positive this is always the case:
>
> ---
> Nov 22 11:10:32 lexiconn2 dovecot: Panic: POP3(techjm): file istream.c: line 
> 76 (i_stream_read): assertion failed: (_stream->
> skip != _stream->pos)
> Nov 22 11:10:32 lexiconn2 dovecot: POP3(techjm): Raw backtrace: pop3 
> [0x80c38f0] -> pop3 [0x80c394a] -> pop3 [0x80c324c] -> p
> op3(i_stream_read+0xda) [0x80c7dda] -> pop3 [0x80c9c6b] -> 
> pop3(i_stream_read+0x2d) [0x80c7d2d] -> pop3 [0x80b9abe] -> pop3(i
> _stream_read+0x2d) [0x80c7d2d] -> pop3(i_stream_read_data+0x1d) [0x80c7e3d] 
> -> pop3(message_get_body_size+0x5c) [0x80be85c] -
>> pop3(index_mail_init_stream+0x151) [0x8089571] -> pop3 [0x80717a2] -> 
> pop3(index_mail_get_virtual_size+0x76) [0x80882b6] ->
> pop3(client_create+0x282) [0x8059c72] -> pop3(main+0x403) [0x805ba83] -> 
> /lib/libc.so.6(__libc_start_main+0xdc) [0x492dec] -
>> pop3 [0x8059351]

We're seeing something similar in 1.1.7:

Dec  1 12:49:33 xxx dovecot: pop3-login: Login: user=<jstuart>, 
method=LOGIN, rip=1.2.3.4, lip=5.6.7.8, TLS
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): Effective uid=778, gid=510
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): mbox: 
data=~/:INBOX=/var/spool/mail/jstuart
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): fs: root=/home/jstuart, 
index=, control=, inbox=/var/spool/mail/jstuart
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): Next message unexpectedly lost 
from 17090
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): Next message unexpectedly lost 
from 17090
Dec  1 12:49:33 xxx dovecot: Panic: POP3(jstuart): file istream.c: line 81 
(i_stream_read): assertion failed: (_stream->skip != _stream->pos)
Dec  1 12:49:33 xxx dovecot: POP3(jstuart): Raw backtrace: pop3 
[0x80c3a30] -> pop3 [0x80c3a8a] -> pop3 [0x80c338c] -> 
pop3(i_stream_read+0xda) [0x80c7f4a] -> pop3 [0x80c9e3b] -> 
pop3(i_stream_read+0x2d) [0x80c7e9d] -> pop3 [0x80b9bfe] -> 
pop3(i_stream_read+0x2d) [0x80c7e9d] -> pop3(i_stream_read_data+0x1d) 
[0x80c7fad] -> pop3(message_get_body_size+0x5c) [0x80be99c] -> 
pop3(index_mail_init_stream+0x151) [0x80896b1] -> pop3 [0x80718a2] -> 
pop3(index_mail_get_virtual_size+0x76) [0x80883f6] -> 
pop3(client_create+0x282) [0x8059ca2] -> pop3(main+0x403) [0x805bab3] -> 
/lib/libc.so.6(__libc_start_main+0xdc) [0x125dec] -> pop3 [0x8059381]
Dec  1 12:49:33 xxx dovecot: child 17331 (pop3) killed with signal 6

dovecot -n
# 1.1.7: /usr/local/etc/dovecot.conf
# OS: Linux 2.6.18-53.1.14.el5PAE i686 CentOS release 5.2 (Final)
protocols: imap imaps pop3 pop3s
ssl_cert_file: /usr/local/apache/conf/ssl.crt/ssl.cert
ssl_key_file: /usr/local/apache/conf/ssl.key/ssl.key
ssl_cipher_list: HIGH:MEDIUM:+TLSv1:!SSLv2:+SSLv3
disable_plaintext_auth: no
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:~/:INBOX=/var/spool/mail/%u
mail_debug: yes
mail_full_filesystem_access: yes
mmap_disable: yes
fsync_disable: yes
mbox_read_locks: fcntl flock
mbox_write_locks: fcntl flock
mbox_very_dirty_syncs: yes
mail_drop_priv_before_exec: yes
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_process_size: 512
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_uidl_format(default): %08Xu%08Xv
pop3_uidl_format(imap): %08Xu%08Xv
pop3_uidl_format(pop3): %08Xv%08Xu
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
auth default:
   mechanisms: plain login
   username_format: %Lu
   verbose: yes
   passdb:
     driver: shadow
   userdb:
     driver: passwd


We're seeing a handful of these errors each day, and many times there is 
no other process (i.e. pine, webmail, etc...) accessing the mbox file at 
the same time. Core files are not cooperating but if we can get one, we'll 
provide those details as well.

Thanks.

Rob