Hi,
during the store of the messages, I find the following doveadm errors:

2019-10-02 09:22:19 auth: Debug: ldap(test.pop@test.xxx.it,10.11.47.60): result: mailMessageStore=1/1/2/0/8/7/2/1120872_91093 mailQuota=52428800; mailQuota,mailMessageStore unused
2019-10-02 09:22:19 auth: Debug: ldap(test.pop@test.xxx.it,10.11.47.60): Finished userdb lookup
2019-10-02 09:22:19 auth: Debug: userdb out: USER    1    test.pop@test.xxx.it    home=/store/mailbox/mailbox_test/1/1/2/0/8/7/2/1120872_91093    quota_rule=*:bytes=52428800    mail_plugins+=
2019-10-02 09:22:19 doveadm(test.pop@test.xxx.it)<180667><MO3BGytQlF27wQIAxhuf8Q>: Fatal: master: service(doveadm): child 180667 killed with signal 11 (core dumped)
2019-10-02 09:22:19 auth: Debug: master in: USER    1    test.pop@test.xxx.it    service=doveadm    lip=192.160.10.100    lport=924    rip=10.11.47.60    rport=56515
2019-10-02 09:22:19 auth: Debug: ldap(test.pop@test.xxx.it,10.11.47.60): Performing userdb lookup

This problem occurs only with the quota plugin enabled.

Can you help me?

Best regards

Domenico

-----------------------------------------------------

(gdb)
#0  clear (this=0x0) at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/util/VoidMap.h:123
#1  lucene::search::FieldSortedHitQueue::_shutdown () at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/search/FieldSortedHitQueue.cpp:60
#2  0x00007f4b37a62e96 in _lucene_shutdown () at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/StdHeader.cpp:33
#3  0x00007f4b3b2f2fbb in module_dir_deinit (modules=<optimized out>) at module-dir.c:578
#4  0x00007f4b3b2f3001 in module_dir_unload (modules=modules@entry=0x7f4b3b8e1380 <mail_storage_service_modules>) at module-dir.c:590
#5  0x00007f4b3b5dd264 in mail_storage_service_deinit (_ctx=_ctx@entry=0x55ea409b7838) at mail-storage-service.c:1730
#6  0x000055ea3f4a3d35 in doveadm_mail_cmd_exec (ctx=ctx@entry=0x55ea409b77f8, wildcard_user=wildcard_user@entry=0x0) at doveadm-mail.c:673
#7  0x000055ea3f4a4bbd in doveadm_cmd_ver2_to_mail_cmd_wrapper (cctx=<optimized out>) at doveadm-mail.c:1144
#8  0x000055ea3f4b5c98 in doveadm_cmd_run_ver2 (argc=argc@entry=1, argv=argv@entry=0x55ea40997150, cctx=cctx@entry=0x7fff9a1cb990) at doveadm-cmd.c:574
#9  0x000055ea3f4ba020 in doveadm_cmd_server_run_ver2 (cctx=0x7fff9a1cb990, argv=0x55ea40997150, argc=1, conn=0x55ea409ebbd8) at client-connection-tcp.c:178
#10 doveadm_cmd_handle (cctx=0x7fff9a1cb990, argv=0x55ea40997150, argc=1, cmd_name=<optimized out>, conn=0x55ea409ebbd8) at client-connection-tcp.c:342
#11 client_handle_command (args=<optimized out>, conn=0x55ea409ebbd8) at client-connection-tcp.c:415
#12 client_connection_tcp_input (conn=0x55ea409ebbd8) at client-connection-tcp.c:561
#13 0x00007f4b3b2e855f in io_loop_call_io (io=0x55ea409c5b10) at ioloop.c:704
#14 0x00007f4b3b2e9fa3 in io_loop_handler_run_internal (ioloop=ioloop@entry=0x55ea4099fcb0) at ioloop-epoll.c:221
#15 0x00007f4b3b2e8666 in io_loop_handler_run (ioloop=ioloop@entry=0x55ea4099fcb0) at ioloop.c:756
#16 0x00007f4b3b2e8888 in io_loop_run (ioloop=0x55ea4099fcb0) at ioloop.c:729
#17 0x00007f4b3b25b2d3 in master_service_run (service=0x55ea4099fb40, callback=callback@entry=0x55ea3f4bd260 <client_connected>) at master-service.c:781
#18 0x000055ea3f493421 in main (argc=1, argv=0x55ea4099f890) at main.c:151

(gdb) bt full
#0  clear (this=0x0) at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/util/VoidMap.h:123
No locals.
#1  lucene::search::FieldSortedHitQueue::_shutdown () at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/search/FieldSortedHitQueue.cpp:60
No locals.
#2  0x00007f4b37a62e96 in _lucene_shutdown () at /usr/src/debug/clucene-core-2.3.3.4/src/core/CLucene/StdHeader.cpp:33
No locals.
#3  0x00007f4b3b2f2fbb in module_dir_deinit (modules=<optimized out>) at module-dir.c:578
        _data_stack_cur_id = 4
        module = 0x55ea40a048b0
        rev = 0x55ea4099ac18
        i = <optimized out>
        count = 6
#4  0x00007f4b3b2f3001 in module_dir_unload (modules=modules@entry=0x7f4b3b8e1380 <mail_storage_service_modules>) at module-dir.c:590
        module = <optimized out>
        next = <optimized out>
#5  0x00007f4b3b5dd264 in mail_storage_service_deinit (_ctx=_ctx@entry=0x55ea409b7838) at mail-storage-service.c:1730
        ctx = 0x55ea409f0bf8
#6  0x000055ea3f4a3d35 in doveadm_mail_cmd_exec (ctx=ctx@entry=0x55ea409b77f8, wildcard_user=wildcard_user@entry=0x0) at doveadm-mail.c:673
        cctx = <optimized out>
        cli = <optimized out>
        ret = <optimized out>
        error = 0x7f4b3b22d2f7 <__x86_return_thunk+5> "\363\220\017\256\350\353\371H\215d$\b\303\350\a"
#7  0x000055ea3f4a4bbd in doveadm_cmd_ver2_to_mail_cmd_wrapper (cctx=<optimized out>) at doveadm-mail.c:1144
        mctx = 0x55ea409b77f8
        wildcard_user = <optimized out>
        fieldstr = 0x55ea40997310 "͒\t7K\177"
        pargv = {arr = {buffer = 0x55ea409b7a28, element_size = 8}, v = 0x55ea409b7a28, v_modifiable = 0x55ea409b7a28}
        full_args = {arr = {buffer = <optimized out>, element_size = 8}, v = <optimized out>, v_modifiable = <optimized out>}
        i = <optimized out>
        cli = <optimized out>
        tcp_server = <optimized out>
        mail_cmd = {alloc = 0x7f4b37098d00 <cmd_quota_get_alloc>, name = 0x7f4b370992b6 "quota get", usage_args = 0x7f4b37099291 ""}
        dashdash = 0x55ea3f4e07ca "--"
        args_pos = 1
#8  0x000055ea3f4b5c98 in doveadm_cmd_run_ver2 (argc=argc@entry=1, argv=argv@entry=0x55ea40997150, cctx=cctx@entry=0x7fff9a1cb990) at doveadm-cmd.c:574
        param = <optimized out>
        pargv = {arr = {buffer = 0x55ea40997410, element_size = 104}, v = 0x55ea40997410, v_modifiable = 0x55ea40997410}
        opts = {arr = {buffer = <optimized out>, element_size = 32}, v = <optimized out>, v_modifiable = <optimized out>}
        pargc = 4
        c = -1
        li = 102607314
        pool = 0x55ea40997240
        optbuf = 0x55ea40997258
        __func__ = "doveadm_cmd_run_ver2"
#9  0x000055ea3f4ba020 in doveadm_cmd_server_run_ver2 (cctx=0x7fff9a1cb990, argv=0x55ea40997150, argc=1, conn=0x55ea409ebbd8) at client-connection-tcp.c:178
No locals.
#10 doveadm_cmd_handle (cctx=0x7fff9a1cb990, argv=0x55ea40997150, argc=1, cmd_name=<optimized out>, conn=0x55ea409ebbd8) at client-connection-tcp.c:342
        mail_cmd = <optimized out>
        mctx = <optimized out>
        cmd_ver2 = <optimized out>
        prev_ioloop = 0x55ea4099fcb0
        cmd = 0x0
#11 client_handle_command (args=<optimized out>, conn=0x55ea409ebbd8) at client-connection-tcp.c:415
        cctx = {cmd = 0x55ea409b53d8, argc = 4, argv = 0x55ea40997448, username = 0x55ea40997119 "test.pop@test.xxx.it", local_ip = {family = 2, u = {ip6 = {__in6_u = {
                  __u6_addr8 = "\300\240\nd", '\000' <repeats 11 times>, __u6_addr16 = {41152, 25610, 0, 0, 0, 0, 0, 0}, __u6_addr32 = {1678418112, 0, 0, 0}}}, ip4 = {
                s_addr = 1678418112}}}, remote_ip = {family = 2, u = {ip6 = {__in6_u = {__u6_addr8 = "\n\v/<", '\000' <repeats 11 times>, __u6_addr16 = {2826, 15407, 0, 0, 0, 0, 0,
                    0}, __u6_addr32 = {1009715978, 0, 0, 0}}}, ip4 = {s_addr = 1009715978}}}, local_port = 924, remote_port = 54042, conn_type = DOVEADM_CONNECTION_TYPE_TCP,
          input = 0x55ea409b0db0, output = 0x55ea409b6cf0}
        flags = <optimized out>
        cmd_name = <optimized out>
        argc = <optimized out>
---Type <return> to continue, or q <return> to quit---
#12 client_connection_tcp_input (conn=0x55ea409ebbd8) at client-connection-tcp.c:561
        args = <optimized out>
        _data_stack_cur_id = 3
        line = <optimized out>
        ok = true
        minor = 0
#13 0x00007f4b3b2e855f in io_loop_call_io (io=0x55ea409c5b10) at ioloop.c:704
        ioloop = 0x55ea4099fcb0
        t_id = 2
        __func__ = "io_loop_call_io"
#14 0x00007f4b3b2e9fa3 in io_loop_handler_run_internal (ioloop=ioloop@entry=0x55ea4099fcb0) at ioloop-epoll.c:221
        ctx = 0x55ea409a57a0
        events = <optimized out>
        list = 0x55ea409e9e80
        io = <optimized out>
        tv = {tv_sec = 2147483, tv_usec = 0}
        events_count = <optimized out>
        msecs = <optimized out>
        ret = 1
        i = 0
        call = <optimized out>
        __func__ = "io_loop_handler_run_internal"
#15 0x00007f4b3b2e8666 in io_loop_handler_run (ioloop=ioloop@entry=0x55ea4099fcb0) at ioloop.c:756
        __func__ = "io_loop_handler_run"
#16 0x00007f4b3b2e8888 in io_loop_run (ioloop=0x55ea4099fcb0) at ioloop.c:729
        __func__ = "io_loop_run"
#17 0x00007f4b3b25b2d3 in master_service_run (service=0x55ea4099fb40, callback=callback@entry=0x55ea3f4bd260 <client_connected>) at master-service.c:781
No locals.
#18 0x000055ea3f493421 in main (argc=1, argv=0x55ea4099f890) at main.c:151
        set_roots = {0x7f4b3b57cd00 <master_service_ssl_setting_parser_info>, 0x55ea3f7026a0 <doveadm_setting_parser_info>, 0x0}
        input = {roots = 0x7fff9a1cbb70, config_path = 0x0, preserve_environment = false, preserve_user = false, preserve_home = false, never_exec = false, use_sysexits = false,
          parse_full_config = false, module = 0x55ea3f4dcd3a "doveadm", service = 0x55ea3f4dcd3a "doveadm", username = 0x0, local_ip = {family = 0, u = {ip6 = {__in6_u = {
                  __u6_addr8 = '\000' <repeats 15 times>, __u6_addr16 = {0, 0, 0, 0, 0, 0, 0, 0}, __u6_addr32 = {0, 0, 0, 0}}}, ip4 = {s_addr = 0}}}, remote_ip = {family = 0, u = {
              ip6 = {__in6_u = {__u6_addr8 = '\000' <repeats 15 times>, __u6_addr16 = {0, 0, 0, 0, 0, 0, 0, 0}, __u6_addr32 = {0, 0, 0, 0}}}, ip4 = {s_addr = 0}}}, local_name = 0x0}
        output = {specific_services = 0x0, service_uses_local = false, service_uses_remote = false, used_local = false, used_remote = false, permission_denied = false}
        error = 0x7f4b3aca3ca7 "__vdso_getcpu"
        c = <optimized out>
(gdb)


#  2.3.7.2 (3c910f64b): /new_config/dovecot/dovecot_test/dovecot.conf
# Pigeonhole version 0.5.7.2 (7372921a)
# OS: Linux 3.10.0-957.21.3.el7.x86_64 x86_64 CentOS Linux release 7.6.1810 (Core) 
# Hostname: pop10
auth_debug = yes
auth_master_user_separator = *
auth_username_format =
base_dir = /data/dovecot/var/run/dovecot_test
default_vsz_limit = 768 M
dict {
  sqlquota = mysql:/new_config/dovecot/common/dovecot-dict-sql.conf.ext
}
disable_plaintext_auth = no
doveadm_password = # hidden, use -P to show it
first_valid_gid = 101
first_valid_uid = 102
imap_id_send =
import_environment = TZ
info_log_path = /LOGS/dovecot/dovecot_test.log
instance_name = dovecot_test
listen = dovecot_test
log_path = /LOGS/dovecot/dovecot_test.log
log_timestamp = "%Y-%m-%d %H:%M:%S "
mail_gid = 101
mail_location = maildir:%h/Maildir
mail_max_userip_connections = 50
mail_plugins = quota mail_log notify virtual fts fts_lucene
mail_uid = 102
maildir_broken_filename_sizes = yes
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 vnd.dovecot.debug
mbox_write_locks = fcntl
namespace {
  hidden = yes
  list = no
  location = virtual:/new_config/dovecot/common/virtual:INDEX=~/virtual:SUBSCRIPTIONS=.subscriptions/%u
  prefix = Messaggi in arrivo.
  separator = .
  subscriptions = no
}
namespace inbox {
  inbox = yes
  location =
  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 = INBOX.
  separator = .
  subscriptions = yes
  type = private
}
passdb {
  args = /new_config/dovecot/common/passwd.masterusers
  driver = passwd-file
  master = yes
}
passdb {
  args = /new_config/dovecot/dovecot_test/dovecot-ldap.conf
  driver = ldap
}
passdb {
  args = /new_config/dovecot/common/dovecot-ldap-multiuser.conf
  driver = ldap
  master = yes
}
passdb {
  args = /new_config/dovecot/common/dovecot-ldap-webmaillight.conf.ext
  driver = ldap
  master = yes
}
plugin {
  fts = lucene
  fts_autoindex = yes
  fts_autoindex_max_recent = 1000
  fts_lucene =
  mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename flag_change save mailbox_create
  mail_log_fields = uid box msgid size flags
  quota = dict:User quota::proxy::sqlquota
  quota_rule2 = INBOX.Trash:storage=+100M
  sieve_default = /new_config/dovecot/common/default.sieve
  sieve_extensions = +vnd.dovecot.debug
}
postmaster_address = posta@fooo.it
service anvil {
  client_limit = 8000
}
service auth {
  client_limit = 12000
  unix_listener auth-userdb {
    mode = 0600
  }
}
service dict {
  process_limit = 7500
  process_min_avail = 10
  unix_listener dict {
    mode = 0600
    user = dovecot
  }
}
service doveadm {
  chroot =
  client_limit = 1
  drop_priv_before_exec = no
  executable = doveadm-server
  extra_groups =
  group =
  idle_kill = 0
  inet_listener {
    port = 924
  }
  privileged_group =
  process_limit = 0
  process_min_avail = 10
  protocol =
  service_count = 100
  type =
  unix_listener doveadm-server {
    group =
    mode = 0600
    user =
  }
  user =
}
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
  process_limit = 5000
  process_min_avail = 10
}
service imap {
  drop_priv_before_exec = yes
  process_limit = 5000
  process_min_avail = 10
}
service lmtp {
  inet_listener lmtp {
    port = 24
  }
  process_limit = 2500
  process_min_avail = 10
}
service managesieve-login {
  inet_listener sieve {
    port = 4190
  }
  process_min_avail = 0
  service_count = 1
  vsz_limit = 64 M
}
service managesieve {
  drop_priv_before_exec = yes
  process_limit = 1024
}
service pop3-login {
  inet_listener pop3 {
    port = 110
  }
  inet_listener pop3s {
    port = 995
    ssl = yes
  }
  process_limit = 1000
  process_min_avail = 5
}
service pop3 {
  drop_priv_before_exec = yes
  process_limit = 1000
  process_min_avail = 5
}
ssl_cert = </new_config/dovecot/common/certs/dovecot.pem
ssl_key = # hidden, use -P to show it
userdb {
  args = /new_config/dovecot/dovecot_test/dovecot-ldap.conf
  driver = ldap
}
protocol lmtp {
  mail_plugins = quota mail_log notify sieve virtual
}
protocol lda {
  mail_plugins = quota mail_log notify sieve virtual
}
protocol imap {
  mail_plugins = quota imap_quota mail_log notify virtual
}
protocol pop3 {
  mail_plugins = quota mail_log notify virtual
  pop3_uidl_format = UID%u-%v
}