Well, it looks like it occurred during the search to me...
Jan 10 17:05:37 sysvolone dovecot: [ID 583609 mail.crit] imap(user@host.com): Panic: file istream-header-filter.c: line 520 (i_stream_create_header_filter): assertion failed: (ret < 0) Jan 10 17:05:37 sysvolone dovecot: [ID 583609 mail.error] imap(user@host.com): Error: Raw backtrace: /usr/local/lib/dovecot/libdovecot.so.0.0.0'default_fatal_finish+0x3c [0xfee7b050] -> /usr/local/lib/dovecot/libdovecot.so.0.0.0'i_internal_fatal_handler+0x2b [0xfee7bbe7] -> /usr/local/lib/dovecot/libdovecot.so.0.0.0'0x3b239 [0xfee7b239] -> /usr/local/lib/dovecot/libdovecot.so.0.0.0'i_stream_create_header_filter+0x12f [0xfee6598b] -> /usr/local/lib/dovecot/libdovecot-storage.so.0.0.0'index_mail_get_header_stream+0x17c [0xfef050cc] -> /usr/local/lib/dovecot/libdovecot-storage.so.0.0.0'mail_get_header_stream+0x13 [0xfeee8b8b] -> /usr/local/lib/dovecot/libdovecot-storage.so.0.0.0'index_storage_search_next_nonblock+0x5bf [0xfef07807] -> /usr/local/lib/dovecot/libdovecot-storage.so.0.0.0'mailbox_search_next_nonblock+0x2a [0xfeeef4c6] -> /usr/local/libexec/dovecot/imap'cmd_search_more+0x78 [0x806516c] -> /usr/local/libexec/dovecot/imap'imap_search_start+0x18e [0x8065612] -> /usr/local/libexec/dovecot/imap'c Jan 10 17:05:37 sysvolone dovecot: [ID 583609 mail.error] master: Error: service(imap): child 7746 killed with signal 6 (core not dumped - set service imap { drop_priv_before_exec=yes })
I'm not sure if that gives you what you need - it looks like the entire dump didn't get saved.
This is on OpenSolaris 5.11 snv_134
Rick