I can reproduce this by simply issuing:

doveadm reload

GNU gdb (GDB) 7.0.1-debian Copyright (C) 2009 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 "i486-linux-gnu". For bug reporting instructions, please see: http://www.gnu.org/software/gdb/bugs/... Reading symbols from /usr/dovecot-2/libexec/dovecot/auth...done. Reading symbols from /usr/dovecot-2/lib/dovecot/libdovecot.so.0...done. Loaded symbols for /usr/dovecot-2/lib/dovecot/libdovecot.so.0 Reading symbols from /lib/i686/cmov/libcrypt.so.1...Reading symbols from /usr/lib/debug/lib/i686/cmov/libcrypt-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/i686/cmov/libcrypt.so.1 Reading symbols from /lib/libpam.so.0...(no debugging symbols found)...done. Loaded symbols for /lib/libpam.so.0 Reading symbols from /lib/i686/cmov/libdl.so.2...Reading symbols from /usr/lib/debug/lib/i686/cmov/libdl-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/i686/cmov/libdl.so.2 Reading symbols from /lib/i686/cmov/libc.so.6...Reading symbols from /usr/lib/debug/lib/i686/cmov/libc-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/i686/cmov/libc.so.6 Reading symbols from /lib/i686/cmov/librt.so.1...Reading symbols from /usr/lib/debug/lib/i686/cmov/librt-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/i686/cmov/librt.so.1 Reading symbols from /lib/ld-linux.so.2...Reading symbols from /usr/lib/debug/lib/ld-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/ld-linux.so.2 Reading symbols from /lib/i686/cmov/libpthread.so.0...Reading symbols from /usr/lib/debug/lib/i686/cmov/libpthread-2.11.2.so...done. (no debugging symbols found)...done. Loaded symbols for /lib/i686/cmov/libpthread.so.0 Reading symbols from /lib/libgcc_s.so.1...(no debugging symbols found)...done. Loaded symbols for /lib/libgcc_s.so.1 Core was generated by `dovecot/auth'. Program terminated with signal 6, Aborted. #0 0xb772e430 in __kernel_vsyscall () #0 0xb772e430 in __kernel_vsyscall () No symbol table info available. #1 0xb7556751 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 resultvar = <value optimized out> pid = -1217994764 selftid = 22112 #2 0xb7559b82 in *__GI_abort () at abort.c:92 act = {__sigaction_handler = {sa_handler = 0xbfdc3ed0, sa_sigaction = 0xbfdc3ed0}, sa_mask = {__val = {3077757632, 3218882212, 3077800674, 3218882196, 3077323828, 3218882184, 3077880404, 0, 3075510304, 1, 0, 1, 3077757192, 3218882108, 3218882104, 3077532336, 3077526747, 3077739624, 3218882188, 166684304, 0, 3218882256, 3218882184, 3218882196, 3077532029, 3077757192, 0, 725, 3218882216, 3077348830, 3218882188, 10}}, sa_flags = -1076084988, sa_restorer = 0xb772a70c } sigs = {__val = {32, 0 }} #3 0xb76f7695 in default_fatal_finish (type=<value optimized out>, status=<value optimized out>) at failures.c:178 backtrace = 0x9ef6280 "/usr/dovecot-2/lib/dovecot/libdovecot.so.0(+0x37681) [0xb76f7681] -> /usr/dovecot-2/lib/dovecot/libdovecot.so.0(+0x376ef) [0xb76f76ef] -> /usr/dovecot-2/lib/dovecot/libdovecot.so.0(i_error+0) [0xb76d1"... #4 0xb76f76ef in i_internal_fatal_handler (type=LOG_TYPE_PANIC, status=0, fmt=0x806bca4 "file %s: line %d (%s): assertion failed: (%s)", args=0xbfdc3f84 "\017\314\006\bc") at failures.c:607 No locals. #5 0xb76d15de in i_panic ( format=0x806bca4 "file %s: line %d (%s): assertion failed: (%s)") at failures.c:244 No locals. #6 0x080578e0 in auth_request_handler_unref (_handler=0xbfdc3fdc) at auth-request-handler.c:99 handler = 0xa0384f8 __FUNCTION__ = "auth_request_handler_unref" #7 0x08058129 in auth_request_handler_destroy (_handler=0x6) at auth-request-handler.c:117 handler = 0x0 __FUNCTION__ = "auth_request_handler_destroy" #8 0x080516f0 in auth_client_connection_destroy_full ( _conn=<value optimized out>, abort_requests=<value optimized out>) at auth-client-connection.c:355 conn = 0x9fe3bf8 clients = 0x9f82ba8 #9 0x080517b1 in auth_client_connections_deinit () at auth-client-connection.c:407 i = 2 #10 0x0805c1bf in main_deinit (argc=1, argv=0x9efe1c0) at main.c:166 No locals. #11 main (argc=1, argv=0x9efe1c0) at main.c:284 c = <value optimized out>

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