Panic: file istream-seekable.c: line 226

[Eric Mauger]

Hi,

I have a lot of Panic in my logs.
They happen almost every day and never on the same user.
When it happens, the mail is not distributed (it's always lda).
I discovered it because my Sympa server had a lot of users in error.
The last error (below) was a local user sending a mail to 10 users : 3 
of them
never get the email.

I've looked into my logs and discovered it started after the upgrade
from 2.2.27 to 2.3.4 in february. I'm on Debian.

This week, I installed the dovecot repo and upgraded to the very last
and same thing. The error below happened after the latest upgrade.

An example :

Nov 25 11:33:07 mx.igf.cnrs.fr dovecot: 
lda(username_hidden)<4653><A3S4MuIyvl8tEgAAmSH/vg>: Panic: file 
istream-seekable.c: line 230 (read_from_buffer): assertion failed: 
(*ret_r > 0)
Nov 25 11:33:07 mx.igf.cnrs.fr dovecot: 
lda(sebastien.granier)<4653><A3S4MuIyvl8tEgAAmSH/vg>: Error: Raw 
backtrace: /usr/lib/dovecot/libdovecot.so.0(backtrace_append+0x3d) 
[0x7f49a56d4eed] -> /usr/lib/dovecot/libdovecot.so.0(backtrace_get+0x1e) 
[0x7f49a56d500e] -> /usr/lib/dovecot/libdovecot.so.0(+0xf465b) 
[0x7f49a56de65b] -> /usr/lib/dovecot/libdovecot.so.0(+0xf46c1) 
[0x7f49a56de6c1] -> /usr/lib/dovecot/libdovecot.so.0(+0x514a6) 
[0x7f49a563b4a6] -> /usr/lib/dovecot/libdovecot.so.0(+0x53cfb) 
[0x7f49a563dcfb] -> /usr/lib/dovecot/libdovecot.so.0(+0x1074a1) 
[0x7f49a56f14a1] -> /usr/lib/dovecot/libdovecot.so.0(+0x1078f6) 
[0x7f49a56f18f6] -> /usr/lib/dovecot/libdovecot.so.0(i_stream_stat+0x34) 
[0x7f49a56eaab4] -> /usr/lib/dovecot/libdovecot-storage.so.0(+0xb1396) 
[0x7f49a5852396] -> /usr/lib/dovecot/libdovecot-storage.so.0(+0xb1472) 
[0x7f49a5852472] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mail_get_physical_size+0x38) 
[0x7f49a57ef0c8] -> /usr/lib/dovecot/libdovecot-lda.so.0(+0x4005) 
[0x7f49a5907005] -> 
/usr/lib/dovecot/libdovecot-lda.so.0(mail_deliver_init+0x141) 
[0x7f49a5908101] -> /usr/lib/dovecot/deliver(main+0x879) 
[0x562d1c0e6f99] -> 
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7f49a543e09b] 
-> /usr/lib/dovecot/deliver(_start+0x2a) [0x562d1c0e76ea]

My configuration :
dovecot -n
# 2.3.11.3 (502c39af9): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.11 (6c69c917)
# OS: Linux 4.19.0-9-amd64 x86_64 Debian 10.6
# Hostname: mx.igf.cnrs.fr
auth_username_format =
disable_plaintext_auth = no
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes
mail_location = maildir:~/maildir
mail_plugins = fts
mail_privileged_group = mail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy include variables body enotify 
environment mailbox date index ihave duplicate mime foreverypart 
extracttext
namespace inbox {
   inbox = yes
   location =
   mailbox Ads {
     auto = subscribe
   }
   mailbox Drafts {
     special_use = \Drafts
   }
   mailbox Junk {
     special_use = \Junk
   }
   mailbox Sent {
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     special_use = \Trash
   }
   prefix =
   separator = .
   type = private
}
passdb {
   driver = pam
}
plugin {
   sieve = file:~/sieve;active=~/.dovecot.sieve
   sieve_after = /etc/dovecot/sieve.d
}
protocols = " imap sieve pop3 sieve"
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0666
     user = postfix
   }
}
service imap-login {
   process_min_avail = 16
   service_count = 0
}
service managesieve-login {
   inet_listener sieve {
     port = 4190
   }
}
service stats {
   unix_listener stats-reader {
     group = dovecot
     mode = 0666
     user = root
   }
   unix_listener stats-writer {
     group = dovecot
     mode = 0666
     user = root
   }
}
ssl_cert = </etc/dovecot/ssl/certs/mx_igf_cnrs_fr_with_CA.crt
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
syslog_facility = local2
userdb {
   driver = passwd
}
verbose_proctitle = yes
protocol lda {
   mail_plugins = fts sieve
   syslog_facility = local2
}

Thanks,

-- 
Eric Mauger | Administrateur système et réseau
IGF UMR5203 | https://www.igf.cnrs.fr