Hi folks,

Not sure how much extra information I'll be able to provide on this, but I'm experiencing a consistent, reproducible dsync backup error with a single, specific account I'm trying to migrate from UW-IMAP / Panda (mix mailbox) to a Dovecot 2.2.32 cluster. Didn't spot any core files laying around.

Doveadm backup output, dovecot --version and dovecot -n below:

server:~# doveadm -Dv -o imapc_user=username-dc -o imapc_password=password backup -R -u username -x .mailboxlist -x .procmailrc -x vacation.msg -x .bash_history -x .Xauthority -x remote_pinerc imapc: Debug: Loading modules from directory: /usr/lib64/dovecot Debug: Module loaded: /usr/lib64/dovecot/lib01_acl_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib15_notify_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_replication_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib20_zlib_plugin.so Debug: Loading modules from directory: /usr/lib64/dovecot/doveadm Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message) Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_sieve_plugin.so Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: undefined symbol: fts_user_get_language_list (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_mail_crypt_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/libdoveadm_mail_crypt_plugin.so: undefined symbol: mail_crypt_box_get_pvt_digests (this is usually intentional, so just ignore this message) doveadm(username): Debug: Effective uid=35000, gid=35000, home=/storagedisk/username doveadm(username): Debug: acl: No acl setting - ACLs are disabled doveadm(username): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=mdbox:~/mdbox doveadm(username): Debug: fs: root=/storagedisk/username/mdbox, index=, indexpvt=, control=, inbox=, alt= doveadm(username): Debug: Namespace : Using permissions from /storagedisk/username/mdbox: mode=0700 gid=default dsync(username): Debug: Effective uid=35000, gid=35000, home=/storagedisk/username dsync(username): Debug: acl: No acl setting - ACLs are disabled dsync(username): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=imapc: dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Created new connection dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Looking up IP address (reconnect_ok=true, last_connect=1506608870) dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Connecting to 192.168.0.100:143 dsync(username): Info: imapc(panda-imap-server.contoso.com:143): Connected to 192.168.0.100:143 (local 192.168.0.200:33630) dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Server capabilities: IMAP4REV1 I18NLEVEL=1 LITERAL+ SASL-IR LOGIN-REFERRALS STARTTLS dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Authenticating as username-dc dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Server capabilities: IMAP4REV1 I18NLEVEL=1 LITERAL+ IDLE UIDPLUS NAMESPACE CHILDREN MAILBOX-REFERRALS BINARY UNSELECT WITHIN SORT THREAD=REFERENCES THREAD=ORDEREDSUBJECT MULTIAPPEND SCAN dsync(username): Debug: imapc(panda-imap-server.contoso.com:143): Authenticated successfully dsync(username): Debug: imapc: root=, index=, indexpvt=, control=, inbox=, alt= dsync(username): Debug: brain S: Local mailbox tree: guid=00000000000000000000000000000000 uid_validity=0 uid_next=0 subs=no last_change=0 last_subs=0 dsync(username): Panic: file dsync-ibc.c: line 72 (dsync_ibc_send_mailbox_tree_node): assertion failed: (*name != NULL) dsync(username): Error: Raw backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0x9edee) [0x7f7d4fbfcdee] -> /usr/lib64/dovecot/libdovecot.so.0(default_fatal_handler+0x2a) [0x7f7d4fbfce5a] -> /usr/lib64/dovecot/libdovecot.so.0(i_fatal+0) [0x7f7d4fb8e2cc] -> doveadm(+0x5332b) [0x563357a0032b] -> doveadm(dsync_brain_send_mailbox_tree+0x6e) [0x5633579f12be] -> doveadm(dsync_brain_run+0x49d) [0x5633579ee56d] -> doveadm(+0x290dc) [0x5633579d60dc] -> doveadm(+0x2b21c) [0x5633579d821c] -> doveadm(+0x2be1a) [0x5633579d8e1a] -> doveadm(doveadm_mail_try_run+0x215) [0x5633579d9775] -> doveadm(main+0x46a) [0x5633579c8a9a] -> /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f7d4f7bcc05] -> doveadm(+0x1bc05) [0x5633579c8c05] Aborted

dovecot --version 2.2.32 (dfbe293d4)

dovecot -n:

# 2.2.32 (dfbe293d4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.20 (7cd71ba) # OS: Linux 3.10.0-693.2.2.el7.x86_64 x86_64 Red Hat Enterprise Linux Server release 7.4 (Maipo) auth_master_user_separator = * auth_username_format = %Ln disable_plaintext_auth = no doveadm_password = # hidden, use -P to show it first_valid_uid = 35000 imapc_features = rfc822.size fetch-headers imapc_host = panda-imap-server.contoso.com imapc_user = %u last_valid_uid = 35000 mail_location = mdbox:~/mdbox mail_plugins = " zlib acl notify replication" mail_prefetch_count = 20 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 spamtest spamtestplus vnd.dovecot.duplicate mbox_write_locks = fcntl 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 = } passdb { args = /etc/dovecot/conf.d/dovecot-ldap.conf.ext driver = ldap } plugin { mail_replica = tcp:otherserver.contoso.com:1109 sieve = ~/.dovecot.sieve sieve_before = /etc/sieve.before sieve_dir = ~/sieve sieve_extensions = +spamtest +spamtestplus +vnd.dovecot.duplicate sieve_spamtest_max_value = 100 sieve_spamtest_status_header = X-PerlMx-Spam: Gauge=[[:alnum:]]+, Probability=(-?[[:digit:]]+)%.* sieve_spamtest_status_type = score zlib_save = gz zlib_save_level = 6 } protocols = imap lmtp sieve service aggregator { fifo_listener replication-notify-fifo { user = vmail } unix_listener replication-notify { user = vmail } } service doveadm { inet_listener { port = 1109 } } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } } service lmtp { inet_listener lmtp { port = 24 } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { group = vmail mode = 0660 user = vmail } } userdb { args = /etc/dovecot/conf.d/dovecot-ldap.conf.ext driver = ldap } protocol lmtp { mail_plugins = " zlib acl notify replication sieve" } protocol lda { mail_plugins = " zlib acl notify replication sieve" }