As promised, here is the bug report:

# dovecot -n # 1.1.alpha2: /usr/local/etc/dovecot.conf protocols: imap pop3 ssl_cert_file: /etc/postfix/server.pem ssl_key_file: /etc/postfix/server.pem 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_location: maildir:/mnt/shared/mail/%u:INDEX=/var/indexes/%u 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_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 auth default: passdb: driver: pam passdb: driver: passwd userdb: driver: passwd socket: type: listen client: path: /usr/local/var/run/dovecot/auth-client mode: 436 master: path: /usr/local/var/run/dovecot/auth-master mode: 384 user: root group: dovecot

#uname -a Linux ns2 2.6.21-2-sparc64 #1 Thu Jul 12 12:33:00 UTC 2007 sparc64 GNU/Linux

# cat /etc/debian_version lenny/sid

Mailstore is NFS mounted, indexes on local disk. I'm upgrading from dovecot 1.0.3, the client is Evolution. When accessing any directory besides Inbox I get temporary failure and in the logs I see

Aug 8 01:23:39 ns2 dovecot: child 25167 (imap) killed with signal 10

here is a bt full of the core dump:

GNU gdb 6.4.90-debian Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "sparc-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1".

Reading symbols from /lib/libdl.so.2...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/ld-linux.so.2...done. Loaded symbols for /lib/ld-linux.so.2 Core was generated by `imap'. Program terminated with signal 10, Bus error. #0 mailbox_list_index_sync_write_dir (ctx=0xf75e8, sync_dir=0xf7650, offset_pos=<value optimized out>, partial=true) at mailbox-list-index-sync.c:594 594 new_dir->count = nondeleted_count; (gdb) bt full #0 mailbox_list_index_sync_write_dir (ctx=0xf75e8, sync_dir=0xf7650, offset_pos=<value optimized out>, partial=true) at mailbox-list-index-sync.c:594 dir = <value optimized out> recs = <value optimized out> i = <value optimized out> j = <value optimized out> count = <value optimized out> __PRETTY_FUNCTION__ = "mailbox_list_index_sync_write_dir" #1 0x0007afdc in mailbox_list_index_sync_write (ctx=0xf75e8) at mailbox-list-index-sync.c:867 ret = <value optimized out> #2 0x0007b270 in mailbox_list_index_sync_commit (_ctx=<value optimized out>) at mailbox-list-index-sync.c:918 ctx = (struct mailbox_list_index_sync_ctx *) 0xf75e8 ret = 0 #3 0x00034384 in index_list_sync_deinit (ctx=0xe13f0, status_items=0, status_r=<value optimized out>) at index-mailbox-list-sync.c:204 box = (struct mailbox *) 0xe0b98 list = <value optimized out> ilist = <value optimized out> view = <value optimized out> tmp_status = {messages = 247, recent = 0, unseen = 0, uidvalidity = 1179084420, uidnext = 248, first_unseen_seq = 0, keywords = 0x0} status = (struct mailbox_status *) 0xffb3d594 uid = <value optimized out> seq = <value optimized out> #4 0x0007f57c in mailbox_sync_deinit (_ctx=0xffb3d6b4, status_items=0, status_r=0x0) at mail-storage.c:509 ctx = (struct mailbox_sync_context *) 0x0 #5 0x0002f078 in imap_sync_nonselected (box=0xe0b98, flags=<value optimized out>) at imap-sync.c:210 ctx = (struct mailbox_sync_context *) 0x0 sync_rec = {seq1 = 4289976032, seq2 = 634052, type = 4289976088} #6 0x0002745c in _cmd_select_full (cmd=0xd9338, readonly=false) at cmd-select.c:39 client = (struct client *) 0xd7840 storage = (struct mail_storage *) 0xd5de0 box = (struct mailbox *) 0xe0b98 status = {messages = 666088, recent = 836034, unseen = 1, uidvalidity = 585071112, uidnext = 4160102400, first_unseen_seq = 836008, keywords = 0x1e} mailbox = 0xdc640 "Archivio.storico.2003" #7 0x000275f8 in cmd_select (cmd=0xd9338) at cmd-select.c:93 No locals. #8 0x00028be0 in client_command_input (cmd=0xd9338) at client.c:491 client = (struct client *) 0xd7840 __PRETTY_FUNCTION__ = "client_command_input" #9 0x00028cd0 in client_command_input (cmd=0xd9338) at client.c:548 command = <value optimized out> client = (struct client *) 0xd7840 __PRETTY_FUNCTION__ = "client_command_input" #10 0x00029348 in _client_input (client=0xd7840) at client.c:584 cmd = <value optimized out> __PRETTY_FUNCTION__ = "_client_input" #11 0x00095f10 in io_loop_handler_run (ioloop=<value optimized out>) at ioloop-epoll.c:201 ctx = <value optimized out> event = (const struct epoll_event *) 0xd4a30 list = (struct io_list *) 0xd78a8 io = (struct io_file *) 0xd7490 tv = {tv_sec = 9, tv_usec = 945402} events_count = <value optimized out> t_id = 2 msecs = <value optimized out> ret = 1 i = 0 call = <value optimized out> #12 0x00095184 in io_loop_run (ioloop=0xd49b0) at ioloop.c:303 No locals. #13 0x000311b0 in main (argc=<value optimized out>, argv=0xcc030, envp=0x0) at main.c:299 No locals.