GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...

warning: Can't read pathname for load map: Input/output error.
Reading symbols from /lib/libdl.so.2...Reading symbols from /usr/lib/debug/lib/libdl-2.9.so...done.
done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/librt.so.1...Reading symbols from /usr/lib/debug/lib/librt-2.9.so...done.
done.
Loaded symbols for /lib/librt.so.1
Reading symbols from /usr/lib/libgc.so.1...done.
Loaded symbols for /usr/lib/libgc.so.1
Reading symbols from /lib/libc.so.6...Reading symbols from /usr/lib/debug/lib/libc-2.9.so...done.
done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug/lib/ld-2.9.so...done.
done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib/libpthread.so.0...Reading symbols from /usr/lib/debug/lib/libpthread-2.9.so...done.
done.
Loaded symbols for /lib/libpthread.so.0
Reading symbols from /lib/libgcc_s.so.1...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /usr/local/dovecot12/lib/dovecot/imap/lib10_quota_plugin.so...done.
Loaded symbols for /usr/local/dovecot12/lib/dovecot/imap/lib10_quota_plugin.so
Reading symbols from /usr/local/dovecot12/lib/dovecot/imap/lib11_imap_quota_plugin.so...done.
Loaded symbols for /usr/local/dovecot12/lib/dovecot/imap/lib11_imap_quota_plugin.so
Core was generated by `imap [j.roe@example.com 2a01:198:37a:1::1]'.
Program terminated with signal 11, Segmentation fault.
[New process 12136]
#0  0x000000000047ac5f in index_storage_lock_notify_reset (ibox=0x0) at index-storage.c:379
379             ibox->next_lock_notify = time(NULL) + LOCK_NOTIFY_INTERVAL;
(gdb) bt full
#0  0x000000000047ac5f in index_storage_lock_notify_reset (ibox=0x0) at index-storage.c:379
No locals.
#1  0x000000000044f6b1 in maildir_uidlist_lock_timeout (uidlist=0x22ee9a0, nonblock=false, refresh=true, refresh_when_locked=false) at maildir-uidlist.c:149
        box = (struct mailbox *) 0x22ea890
        control_dir = 0x70 <Address 0x70 out of bounds>
        path = 0x2301b20 ""
        old_mask = 3656138848
        dotlock_flags = 0
        i = 5133251
        ret = 0
#2  0x000000000044f882 in maildir_uidlist_lock (uidlist=0x22ee9a0) at maildir-uidlist.c:203
No locals.
#3  0x0000000000452527 in maildir_uidlist_update (uidlist=0x22ee9a0) at maildir-uidlist.c:1308
        ret = 0
#4  0x000000000044fda0 in maildir_uidlist_deinit (_uidlist=0x7fffd9ec4128) at maildir-uidlist.c:325
        uidlist = (struct maildir_uidlist *) 0x22ee9a0
        __PRETTY_FUNCTION__ = "maildir_uidlist_deinit"
#5  0x000000000044792a in dbox_sync_index_rebuild (mbox=0x22ea890) at dbox-sync-rebuild.c:446
        ctx = {mbox = 0x22ea890, append_ctx = 0x0, view = 0x0, trans = 0x0, cache_ext_id = 6, cache_reset_id = 0, maildir_uidlist = 0x0, mk = 0x0, maildir_new_files = {arr = {buffer = 0x0, element_size = 8}, 
    v = 0x0, v_modifiable = 0x0}, maildir_new_uid = 0, cache_used = 0}
        seq = 3
        offset = 64876
        fnames = (char **) 0x22d3cf0
        i = 0
        count = 0
        ret = 0
#6  0x00000000004457b6 in dbox_sync_begin (mbox=0x22ea890, ctx_r=0x7fffd9ec41d8, close_flush_dirty_flags=false, force=false) at dbox-sync.c:357
        storage = (struct mail_storage *) 0x2292a20
        ctx = (struct dbox_sync_context *) 0x22d4e00
        sync_flags = 6
        i = 0
        ret = 0
        rebuild = false
#7  0x0000000000445900 in dbox_sync (mbox=0x22ea890, close_flush_dirty_flags=false) at dbox-sync.c:396
        sync_ctx = (struct dbox_sync_context *) 0x22ea890
#8  0x000000000044598c in dbox_storage_sync_init (box=0x22ea890, flags=65) at dbox-sync.c:415
        mbox = (struct dbox_mailbox *) 0x22ea890
        ret = 0
#9  0x0000000000488778 in mailbox_sync_init (box=0x22ea890, flags=65) at mail-storage.c:562
No locals.
#10 0x000000000048881e in mailbox_sync (box=0x22ea890, flags=65, status_items=239, status_r=0x7fffd9ec42a0) at mail-storage.c:593
        ctx = (struct mailbox_sync_context *) 0x22ea890
#11 0x0000000000422be3 in select_open (ctx=0x22dc1e8, mailbox=0x50498b "INBOX", readonly=false) at cmd-select.c:273
        client = (struct client *) 0x22daf00
        status = {messages = 3656139488, recent = 32767, unseen = 4354815, uidvalidity = 0, uidnext = 36552744, first_unseen_seq = 0, highest_modseq = 36252192, keywords = 0x7fffd9ec4318, 
  sync_delayed_expunges = 0, nonpermanent_modseqs = 0}
        open_flags = 0
#12 0x0000000000422ff6 in cmd_select_full (cmd=0x22dc090, readonly=false) at cmd-select.c:381
        client = (struct client *) 0x22daf00
        box = (struct mailbox *) 0x22cf228
        ctx = (struct imap_select_context *) 0x22dc1e8
        args = (const struct imap_arg *) 0x22e50d8
        mailbox = 0x50498b "INBOX"
        ret = 32767
        __PRETTY_FUNCTION__ = "cmd_select_full"
#13 0x0000000000423029 in cmd_select (cmd=0x22dc090) at cmd-select.c:388
No locals.
#14 0x00000000004262b6 in client_command_input (cmd=0x22dc090) at client.c:611
        client = (struct client *) 0x22daf00
        command = (struct command *) 0x7022dc1b8
        __PRETTY_FUNCTION__ = "client_command_input"
#15 0x00000000004264e1 in client_command_input (cmd=0x22dc090) at client.c:660
        client = (struct client *) 0x22daf00
        command = (struct command *) 0x22cf228
        __PRETTY_FUNCTION__ = "client_command_input"
#16 0x0000000000426603 in client_handle_next_command (client=0x22daf00, remove_io_r=0x7fffd9ec445d) at client.c:701
        size = 22
#17 0x0000000000426684 in client_handle_input (client=0x22daf00) at client.c:713
        _data_stack_cur_id = 3
        ret = true
        remove_io = false
        handled_commands = true
        __PRETTY_FUNCTION__ = "client_handle_input"
#18 0x00000000004267e0 in client_input (client=0x22daf00) at client.c:752
        cmd = (struct client_command_context *) 0xd9ec44cc
        output = (struct ostream *) 0x22dae68
        bytes = 56
        __PRETTY_FUNCTION__ = "client_input"
#19 0x00000000004e2843 in io_loop_handler_run (ioloop=0x2295f80) at ioloop-epoll.c:208
        ctx = (struct ioloop_handler_context *) 0x229cfc0
        events = (struct epoll_event *) 0x22cf800
        event = (const struct epoll_event *) 0x22cf800
        list = (struct io_list *) 0x229af80
        io = (struct io_file *) 0x2295c00
        tv = {tv_sec = 1799, tv_usec = 999469}
        events_count = 3
        t_id = 2
        msecs = 1800000
        ret = 1
        i = 0
        j = 0
        call = true
#20 0x00000000004e1a3c in io_loop_run (ioloop=0x2295f80) at ioloop.c:338
No locals.
#21 0x000000000043192c in main (argc=3, argv=0x7fffd9ec4648, envp=0x7fffd9ec4668) at main.c:327
No locals.
(gdb)