We're seeing a core dump for a user connecting from IPHONE. The user mail are in NFS mount.

# dovecot --version 2.2.12

# doveconf -n # 2.2.12: /etc/dovecot/dovecot.conf # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.4 auth_cache_negative_ttl = 0 auth_cache_size = 20 M auth_verbose = yes default_client_limit = 4000 default_process_limit = 1000 default_vsz_limit = 2 G director_mail_servers = disable_plaintext_auth = no first_valid_uid = 100 imap_client_workarounds = tb-extra-mailbox-sep delay-newmail tb-lsub-flags log_timestamp = "%Y-%m-%d %H:%M:%S " mail_fsync = always mail_nfs_index = yes mail_nfs_storage = yes mail_plugins = " quota" mbox_dotlock_change_timeout = 1 mins mbox_lock_timeout = 1 mins mmap_disable = yes namespace inbox { hidden = no 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 = separator = / type = private } passdb { args = /etc/dovecot/dovecot-ldap.conf.ext driver = ldap } plugin { quota = fs:Disk quota } pop3_client_workarounds = outlook-no-nuls oe-ns-eoh protocols = " imap pop3" service auth-worker { user = root } service auth { user = $default_internal_user } service imap-login { client_limit = 2000 process_min_avail = 4 service_count = 1 } service imap-postlogin { executable = script-login /usr/local/dovecot-scripts/imap.sh user = root } service imap { executable = imap imap-postlogin process_limit = 4096 } service pop3-login { client_limit = 2000 service_count = 1 } service pop3-postlogin { executable = script-login /usr/local/dovecot-scripts/ipop3.sh user = root } service pop3 { executable = pop3 pop3-postlogin process_limit = 2048 } ssl_ca =

# gdb /usr/lib/dovecot/imap ./5040 GNU gdb (GDB) 7.4.1-debian Copyright (C) 2012 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". For bug reporting instructions, please see: http://www.gnu.org/software/gdb/bugs/... Reading symbols from /usr/lib/dovecot/imap...Reading symbols from /usr/lib/debug/usr/lib/dovecot/imap...done. done. [New LWP 5040]

warning: Can't read pathname for load map: Input/output error. [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Core was generated by `dovecot/imap imap-postlogin'. Program terminated with signal 11, Segmentation fault. #0 0x00007fca22f0ca85 in mail_cache_header_fields_read (cache=cache@entry=0x7fca24a04f70) at mail-cache-fields.c:369 369 for (p = names; p != end && *p != '\0'; p++) ; (gdb) bt full #0 0x00007fca22f0ca85 in mail_cache_header_fields_read (cache=cache@entry=0x7fca24a04f70) at mail-cache-fields.c:369 field_hdr = 0x7fca21d37010 field = {name = 0x0, idx = 0, type = MAIL_CACHE_FIELD_FIXED_SIZE, field_size = 0, decision = MAIL_CACHE_DECISION_NO, last_used = 0} last_used = 0x7fca21d3701c sizes = 0x7fca79d3701c types = 0x7fcad1d3701c