Segfault in lib11_trash_plugin.so

[Василий Севостьянов]

After a recent update of dovecot to 2.2.devel (d81a83b) I started to get
errors like that:

Jul 26 07:34:44 mx kernel: pop3[17311]: segfault at 1ee74b0d5 ip
00000001ee74b0d5 sp 00007ffe593dc3c0 error 14 in lib11_trash_plugin.so[
7f66edce2000+3000]
Jul 26 08:11:25 mx dovecot: pop3(xxxxxxxx): Fatal: master: service(pop3):
child 17311 killed with signal 11 (core dumps disabled)

My dovecot configuration follows:
# 2.2.devel (d81a83b): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.devel (3f51b82)
# OS: Linux 3.16.0-4-amd64 x86_64 Debian 8.5 ext4
auth_default_realm = euct.ru
auth_mechanisms = plain login
dict {
  acl = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
  quota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes
listen = *
login_greeting = Hello.
mail_gid = 5000
mail_location = maildir:/home/vmail/%d/%u
mail_max_userip_connections = 25
mail_plugins = " quota trash"
mail_uid = 5000
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 {
  list = children
  location = maildir:/home/vmail/%d/%%n:INDEX=/home/vmail/%d/%n/Shared/%%u
  prefix = Shared/%%u/
  separator = /
  subscriptions = yes
  type = shared
}
namespace inbox {
  inbox = yes
  list = yes
  location =
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    autoexpunge = 1 weeks
    special_use = \Trash
  }
  prefix =
  separator = /
  type = private
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
plugin {
  acl = vfile
  acl_shared_dict = proxy::acl
  deleted_to_trash_folder = Trash
  quota = dict:User quota::proxy::quota
  quota_grace = 50M
  quota_rule = *:storage=250M
  quota_rule2 = Trash:storage=+50M
  quota_warning = storage=95%% quota-warning 95 %u
  quota_warning2 = storage=80%% quota-warning 80 %u
  sieve = ~/sieve/.dovecot.sieve
  sieve_dir = ~/sieve
  sieve_vacation_default_period = 7d
  sieve_vacation_max_period = 30d
  sieve_vacation_min_period = 1d
  trash = /etc/dovecot/dovecot-trash.conf.ext
}
postmaster_address = postmaster at euct.ru
protocols = " imap sieve pop3"
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
  unix_listener auth-userdb {
    group = dovecot
    mode = 0666
    user = vmail
  }
}
service dict {
  unix_listener dict {
    group = dovecot
    mode = 0600
    user = vmail
  }
}
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
service pop3-login {
  inet_listener pop3 {
    port = 110
  }
  inet_listener pop3s {
    port = 995
    ssl = yes
  }
}
service quota-warning {
  executable = script /usr/local/bin/quota-warning.sh
  unix_listener quota-warning {
    user = vmail
  }
  user = dovecot
}
ssl = required
ssl_cert = </etc/letsencrypt/live/mail.euct.ru/fullchain.pem
ssl_dh_parameters_length = 2048
ssl_key = </etc/letsencrypt/live/mail.euct.ru/privkey.pem
ssl_protocols = !SSLv2 !SSLv3
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
protocol lda {
  mail_plugins = " quota trash acl sieve"
}
protocol imap {
  mail_plugins = " quota trash quota imap_quota acl imap_acl
deleted_to_trash"
}