Hello,

Here is a Panic that happened while doing some testing with two servers both running Dovecot v2.2.26 on CentOS 7.

These are test servers owning 32 accounts whose data were copied from our production server.

What I've done is:

server01# doveadm force-resync -A '*' server01# doveadm replicator replicate -f '*'

For 5 accounts I obtained the following crash:

2016-10-28T14:09:43.236946+02:00 server01 dovecot: dsync-server(someuser): Panic: file dsync-brain-mailbox.c: line 358 (dsync_brain_sync_mailbox_deinit): assertion failed: (brain->failed || brain->sync_type == DSYNC_BRAIN_SYNC_TYPE_CHANGED) 2016-10-28T14:09:43.237441+02:00 server01 dovecot: dsync-server(someuser): Error: Raw backtrace: /usr/local/lib/dovecot/libdovecot.so.0(+0x8f7e0) [0x7f3d9318d7e0] -> /usr/local/lib/dovecot/libdovecot.so.0(+0x8f8be) [0x7f3d9318d8be] -> /usr/local/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x7f3d9312b9be] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x438243] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x438da7] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x4368be] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x436c71] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x44becf] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x4c) [0x7f3d931a0c3c] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0xe7) [0x7f3d931a1fd7] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x25) [0x7f3d931a0cc5] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_run+0x38) [0x7f3d931a0e78] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x41fc7e] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x421256] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x433654] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x4c) [0x7f3d931a0c3c] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0xe7) [0x7f3d931a1fd7] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x25) [0x7f3d931a0cc5] -> /usr/local/lib/dovecot/libdovecot.so.0(io_loop_run+0x38) [0x7f3d931a0e78] -> /usr/local/lib/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f3d93131a23] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x413c87] -> /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f3d92d5db15] -> dovecot/doveadm-server 10.0.0.2 someuser slave_recv_mailbox [0x413d25] 2016-10-28T14:09:43.238013+02:00 server01 dovecot: dsync-server(someuser): Fatal: master: service(doveadm): child 96390 killed with signal 6 (core dumps disabled) 2016-10-28T14:09:43.505098+02:00 server01 dovecot: dsync-server(someuser): Error: read(server02.localdomain) failed: read(size=5807) failed: Connection reset by peer (last sent=mailbox_state, last recv=mailbox_state)

Regards, Gilles.