main.ssl_cert_verify failed in buildbot, server crashed after 'shutdown complete'

main.ssl_cert_verify                     w2 [ fail ]  Found warnings/errors in server log file!

        Test ended at 2017-09-04 21:01:05

2017-09-04 21:00:59 2983783312 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld (root[root] @ localhost []): Normal shutdown

2017-09-04 21:00:59 2983783312 [Note] Event Scheduler: Purging the queue. 0 events

2017-09-04 21:00:59 2983783312 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: Shutdown complete

2017-09-04 21:01:01 3086649040 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld (mysqld 10.2.9-MariaDB-log) starting as process 18915 ...

2017-09-04 21:01:01 3086649040 [Warning] Could not increase number of max_open_files to more than 1024 (request: 4162)

2017-09-04 21:01:01 3086649040 [Note] Plugin 'SEQUENCE' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'partition' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'InnoDB' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_DATAFILES' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_TABLESTATS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_LOCKS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_TABLESPACES_SCRUBBING' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMPMEM' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMP_PER_INDEX' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMP' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_DELETED' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMP_RESET' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_LOCK_WAITS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_TABLESPACES_ENCRYPTION' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_BUFFER_PAGE_LRU' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_FIELDS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMPMEM_RESET' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'FEEDBACK' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_COLUMNS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_INDEX_TABLE' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_CMP_PER_INDEX_RESET' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'user_variables' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_INDEX_CACHE' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_FOREIGN_COLS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_BEING_DELETED' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_BUFFER_POOL_STATS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_TRX' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_FOREIGN' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_TABLES' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_DEFAULT_STOPWORD' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_FT_CONFIG' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_BUFFER_PAGE' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_TABLESPACES' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_METRICS' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_INDEXES' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_VIRTUAL' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_MUTEXES' is disabled.

2017-09-04 21:01:01 3086649040 [Note] Plugin 'INNODB_SYS_SEMAPHORE_WAITS' is disabled.

2017-09-04 21:01:01 3086649040 [Warning] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: unknown variable 'loose-feedback-debug-startup-interval=20'

2017-09-04 21:01:01 3086649040 [Warning] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: unknown variable 'loose-feedback-debug-first-interval=60'

2017-09-04 21:01:01 3086649040 [Warning] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: unknown variable 'loose-feedback-debug-interval=60'

2017-09-04 21:01:01 3086649040 [Warning] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: unknown option '--loose-pam-debug'

2017-09-04 21:01:01 3086649040 [Warning] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: unknown variable 'loose-debug-sync-timeout=300'

2017-09-04 21:01:01 3086649040 [Note] Server socket created on IP: '127.0.0.1'.

2017-09-04 21:01:01 3086649040 [Note] Reading of all Master_info entries succeded

2017-09-04 21:01:01 3086649040 [Note] Added new Master_info '' to hash table

2017-09-04 21:01:01 3086649040 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: ready for connections.

Version: '10.2.9-MariaDB-log'  socket: '/usr/local/mariadb-10.2.9-linux-i686/mysql-test/var/tmp/2/mysqld.1.sock'  port: 16020  MariaDB Server

2017-09-04 21:01:01 2984602512 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld (root[root] @ localhost []): Normal shutdown

2017-09-04 21:01:01 2984602512 [Note] Event Scheduler: Purging the queue. 0 events

2017-09-04 21:01:01 2984602512 [Note] /usr/local/mariadb-10.2.9-linux-i686/bin/mysqld: Shutdown complete

170904 21:01:01 [ERROR] mysqld got signal 11 ;

This could be because you hit a bug. It is also possible that this binary

or one of the libraries it was linked against is corrupt, improperly built,

or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help

diagnose the problem, but since we have already crashed, 

something is definitely wrong and this may fail.

Server version: 10.2.9-MariaDB-log

read_buffer_size=131072

max_used_connections=2

thread_count=0

Thread pointer: 0x0

Attempting backtrace. You can use the following information to find out

where mysqld died. If you see no messages after this, something went

terribly wrong...

stack_bottom = 0x0 thread_stack 0x49000

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld(my_print_stacktrace+0x2d)[0x8a6e25d]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld(handle_fatal_signal+0x4df)[0x841652f]

[0x654420]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld[0x8a93728]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld(_Z29one_thread_per_connection_endP3THDb+0x47)[0x816f487]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld(_Z24do_handle_one_connectionP7CONNECT+0x1b9)[0x830cfc9]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld(handle_one_connection+0x3b)[0x830d24b]

/usr/local/mariadb-10.2.9-linux-i686/bin/mysqld[0x863aac8]

/lib/libpthread.so.0[0x11549b]

/lib/libc.so.6(clone+0x5e)[0x82e42e]

The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains

information that should help you find out what is causing the crash.