Hi,

I'm running Dovecot 2.3.9-2 as an IMAP/POP3 Proxy in front of several Dovecotbackends. No Director, only static routing to the backends of each user. The proxies are also working as "SSL offload engines". SystemOS: Debian Stretch (9.11) on LXC Virtualization

Sometimes I get the following errors in mail.err log:

... Mar 10 16:47:24 imap1 dovecot: imap-login: Panic: file iostream-openssl.c: line 599 (openssl_iostream_handle_error): assertion failed: (errno != 0) Mar 10 16:47:24 imap1 dovecot: imap-login: Fatal: master: service(imap-login): child 30431 killed with signal 6 (core dumped) Mar 10 16:47:38 imap1 dovecot: imap-login: Panic: file iostream-openssl.c: line 599 (openssl_iostream_handle_error): assertion failed: (errno != 0) Mar 10 16:47:38 imap1 dovecot: imap-login: Fatal: master: service(imap-login): child 30471 killed with signal 6 (core dumped) ...

Full backtrace of the coredump: ... # gdb /usr/lib/dovecot/imap-login core.imap-login.30471

GNU gdb (Debian 7.12-6) 7.12.0.20161007-git Copyright (C) 2016 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". Type "show configuration" for configuration details. For bug reporting instructions, please see: http://www.gnu.org/software/gdb/bugs/. Find the GDB manual and other documentation resources online at: http://www.gnu.org/software/gdb/documentation/. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /usr/lib/dovecot/imap-login...Reading symbols from /usr/lib/debug/.build-id/3c/24fcde9d366e5cfd7615cc42e013a060d092e5.debug...done. done. [New LWP 30471] [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-login'. Program terminated with signal SIGABRT, Aborted. #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51

warning: Source file is more recent than executable. 51 } (gdb) bt full #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 set = {__val = {0, 140427116827682, 140427117098374, 2147483649, 140427116658101, 0, 140427119440144, 140427116658101, 140427116658080, 140427104016227, 140427119689728, 0, 140427104016288, 140427119440144, 18446744073709551615, 0}} pid = <optimized out> tid = <optimized out> #1 0x00007fb7bc5ba42a in __GI_abort () at abort.c:89 save_stage = 2 act = {__sigaction_handler = {sa_handler = 0x7fff75b21b30, sa_sigaction = 0x7fff75b21b30}, sa_mask = {__val = {0, 140427119702945, 94861876544520, 140427119702945, 140427120378435, 140735167994944, 94861876544520, 140427119702945, 6008397283549395712, 140427119702945, 94861876544520, 140735167994832, 140427101843879, 3, 5, 140427119702945}}, sa_flags = -1130359394, sa_restorer = 0x0} sigs = {__val = {32, 0 }} #2 0x00007fb7bca0c464 in default_fatal_finish (status=0, type=LOG_TYPE_PANIC) at failures.c:459 backtrace = 0x5646c0a5ae4c "" recursed = 0 recursed = 0 #3 fatal_handler_real (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:471 status = 0 #4 0x00007fb7bca0c551 in i_internal_fatal_handler (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:848 No locals. #5 0x00007fb7bc9622e3 in i_panic (format=format@entry=0x7fb7bb85ae70 "file %s: line %d (%s): assertion failed: (%s)") at failures.c:523 ctx = {type = LOG_TYPE_PANIC, exit_status = 0, timestamp = 0x0, timestamp_usecs = 0, log_prefix = 0x0, log_prefix_type_pos = 0} args = {{gp_offset = 40, fp_offset = 48, overflow_arg_area = 0x7fff75b21d20, reg_save_area = 0x7fff75b21c60}} #6 0x00007fb7bb858708 in openssl_iostream_handle_error (ssl_io=ssl_io@entry=0x5646c0a22aa0, ret=-1, type=type@entry=OPENSSL_IOSTREAM_SYNC_TYPE_HANDSHAKE, func_name=func_name@entry=0x7fb7bb85b1a7 "SSL_accept()") at iostream-openssl.c:599 errstr = 0x0 err = 5 __func__ = "openssl_iostream_handle_error" #7 0x00007fb7bb8588ea in openssl_iostream_handshake (ssl_io=0x5646c0a22aa0) at iostream-openssl.c:669 reason = 0x53621d7edb623b00 error = 0x0 ret = <optimized out> __func__ = "openssl_iostream_handshake" #8 0x00007fb7bb8583da in openssl_iostream_more (ssl_io=ssl_io@entry=0x5646c0a22aa0, type=type@entry=OPENSSL_IOSTREAM_SYNC_TYPE_HANDSHAKE) at iostream-openssl.c:546 ret = <optimized out> #9 0x00007fb7bb85a30f in i_stream_ssl_read_real (stream=stream@entry=0x5646c0a5b530) at istream-openssl.c:46 sstream = 0x5646c0a5b530 ssl_io = 0x5646c0a22aa0 buffer = "\234y\345h\226#a\256*\v\216\024\215\250S\227\362\300\003\231\212\027\361\340\353vfv\206_\375\340\362\300\003\231\212\027\361\340\353vfv\206_\375\340kEt6\005\235\273\205\365\211\366\bU\374\212kEt6\005\235\273\205\365\211\366\bU\374\212ڿ\024\221\025\350\351\347\060\005\236}\377\250\266\340ڿ\024\221\025\350\351\347\060\005\236}\377\250\266\340\037p\275x8\334Iu~\215\257\255\322\310W\253\037p\275x8\334Iu~\215\257\255\322\310W\253\264\036N\350\375\f!\310\"\250\033\236%\214\223\242\264\036N\350\375\f!\310\"\250\033\236%\214\223\242\371\v\204\371\v\002\036u\355\324/\301FV\000\000\260\037\262u\377\177\000\000\224\261"... orig_max_buffer_size = 1026 size = 10904244446682811178 ret = <optimized out> total_ret = <optimized out> __func__ = "i_stream_ssl_read_real" #10 0x00007fb7bb85a53e in i_stream_ssl_read (stream=0x5646c0a5b530) at istream-openssl.c:102 sstream = 0x5646c0a5b530 ret = <optimized out> #11 0x00007fb7bca1a305 in i_stream_read_memarea (stream=stream@entry=0x5646c0a5b5b0) at istream.c:313 old_size = 0 ret = <optimized out> __func__ = "i_stream_read_memarea" #12 0x00007fb7bca1a525 in i_stream_read (stream=0x5646c0a5b5b0) at istream.c:271 _stream = 0x5646c0a5b530 ret = <optimized out> #13 0x00007fb7bccd2880 in client_read (client=0x5646c0a59940) at client-common.c:1079 No locals. #14 0x00005646beb83ae3 in imap_client_input (client=<optimized out>) at imap-login-client.c:349 imap_client = 0x5646c0a59940 #15 0x00007fb7bca260c5 in io_loop_call_io (io=0x5646c0a22c80) at ioloop.c:718 ioloop = 0x5646c074ce10 t_id = 2 __func__ = "io_loop_call_io" #16 0x00007fb7bca27afb in io_loop_handler_run_internal (ioloop=ioloop@entry=0x5646c074ce10) at ioloop-epoll.c:222 ---Type <return> to continue, or q <return> to quit--- ctx = 0x5646c074eaa0 io = <optimized out> tv = {tv_sec = 0, tv_usec = 982536} events_count = <optimized out> msecs = <optimized out> ret = <optimized out> i = 0 j = <optimized out> call = <optimized out> __func__ = "io_loop_handler_run_internal" #17 0x00007fb7bca261d9 in io_loop_handler_run (ioloop=<optimized out>) at ioloop.c:770 No locals. #18 0x00007fb7bca26408 in io_loop_run (ioloop=0x5646c074ce10) at ioloop.c:743 __func__ = "io_loop_run" #19 0x00007fb7bc993423 in master_service_run (service=0x5646c074cca0, callback=callback@entry=0x7fb7bccd7d10 ) at master-service.c:809 No locals. #20 0x00007fb7bccd8541 in login_binary_run (binary=<optimized out>, argc=<optimized out>, argv=<optimized out>) at main.c:560 set_pool = 0x5646c0752d10 login_socket = 0x7fb7bccdbfc9 "login" c = <optimized out> #21 0x00007fb7bc5a62e1 in __libc_start_main (main=0x5646beb832f0 <main>, argc=1, argv=0x7fff75b241c8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff75b241b8) at ../csu/libc-start.c:291 result = <optimized out> unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, -6899649731693310855, 94861847442192, 140735168004544, 0, 0, -915335683310285703, -874401070412002183}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x7fff75b241d8, 0x7fb7bd106170}, data = {prev = 0x0, cleanup = 0x0, canceltype = 1974616536}}} not_first_call = <optimized out> #22 0x00005646beb8333a in _start () No symbol table info available. ...

.... (gdb) bt #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 #1 0x00007fb7bc5ba42a in __GI_abort () at abort.c:89 #2 0x00007fb7bca0c464 in default_fatal_finish (status=0, type=LOG_TYPE_PANIC) at failures.c:459 #3 fatal_handler_real (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:471 #4 0x00007fb7bca0c551 in i_internal_fatal_handler (ctx=<optimized out>, format=<optimized out>, args=<optimized out>) at failures.c:848 #5 0x00007fb7bc9622e3 in i_panic (format=format@entry=0x7fb7bb85ae70 "file %s: line %d (%s): assertion failed: (%s)") at failures.c:523 #6 0x00007fb7bb858708 in openssl_iostream_handle_error (ssl_io=ssl_io@entry=0x5646c0a22aa0, ret=-1, type=type@entry=OPENSSL_IOSTREAM_SYNC_TYPE_HANDSHAKE, func_name=func_name@entry=0x7fb7bb85b1a7 "SSL_accept()") at iostream-openssl.c:599 #7 0x00007fb7bb8588ea in openssl_iostream_handshake (ssl_io=0x5646c0a22aa0) at iostream-openssl.c:669 #8 0x00007fb7bb8583da in openssl_iostream_more (ssl_io=ssl_io@entry=0x5646c0a22aa0, type=type@entry=OPENSSL_IOSTREAM_SYNC_TYPE_HANDSHAKE) at iostream-openssl.c:546 #9 0x00007fb7bb85a30f in i_stream_ssl_read_real (stream=stream@entry=0x5646c0a5b530) at istream-openssl.c:46 #10 0x00007fb7bb85a53e in i_stream_ssl_read (stream=0x5646c0a5b530) at istream-openssl.c:102 #11 0x00007fb7bca1a305 in i_stream_read_memarea (stream=stream@entry=0x5646c0a5b5b0) at istream.c:313 #12 0x00007fb7bca1a525 in i_stream_read (stream=0x5646c0a5b5b0) at istream.c:271 #13 0x00007fb7bccd2880 in client_read (client=0x5646c0a59940) at client-common.c:1079 #14 0x00005646beb83ae3 in imap_client_input (client=<optimized out>) at imap-login-client.c:349 #15 0x00007fb7bca260c5 in io_loop_call_io (io=0x5646c0a22c80) at ioloop.c:718 #16 0x00007fb7bca27afb in io_loop_handler_run_internal (ioloop=ioloop@entry=0x5646c074ce10) at ioloop-epoll.c:222 #17 0x00007fb7bca261d9 in io_loop_handler_run (ioloop=<optimized out>) at ioloop.c:770 #18 0x00007fb7bca26408 in io_loop_run (ioloop=0x5646c074ce10) at ioloop.c:743 #19 0x00007fb7bc993423 in master_service_run (service=0x5646c074cca0, callback=callback@entry=0x7fb7bccd7d10 ) at master-service.c:809 #20 0x00007fb7bccd8541 in login_binary_run (binary=<optimized out>, argc=<optimized out>, argv=<optimized out>) at main.c:560 #21 0x00007fb7bc5a62e1 in __libc_start_main (main=0x5646beb832f0 <main>, argc=1, argv=0x7fff75b241c8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff75b241b8) at ../csu/libc-start.c:291 #22 0x00005646beb8333a in _start () .....

I hope this is correct, fact that I'm not very experienced with coreudmps and the debug-process of it.

Many thanks Urban Loesch