rpl.rpl_parallel_mdev6589 fails in buildbot (Assertion `count > 0' failed)

rpl.rpl_parallel_mdev6589 'innodb_plugin,stmt' w4 [ fail ]

        Test ended at 2017-05-17 09:46:32

CURRENT_TEST: rpl.rpl_parallel_mdev6589

mysqltest: In included file "./include/sync_with_master_gtid.inc": 

included from /mnt/buildbot/build/mariadb-10.0.31/mysql-test/suite/rpl/t/rpl_parallel_mdev6589.test at line 116:

At line 43: query 'let $_result= `SELECT master_gtid_wait('$master_pos', $_slave_timeout)`' failed: 2013: Lost connection to MySQL server during query

mysqld: /home/buildbot/buildbot/build/mariadb-10.0.31/sql/rpl_parallel.cc:1869: rpl_parallel_thread* rpl_parallel_thread_pool::get_thread(rpl_parallel_thread**, rpl_parallel_entry*): Assertion `count > 0' failed.

170517  9:46:31 [ERROR] mysqld got signal 6 ;

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: 10.0.31-MariaDB-debug

key_buffer_size=1048576

read_buffer_size=131072

max_used_connections=5

max_threads=153

thread_count=5

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 61724 K  bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0xa1085b0

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 = 0xa8a24e20 thread_stack 0x48000

mysys/stacktrace.c:267(my_print_stacktrace)[0x8a89035]

sql/signal_handler.cc:161(handle_fatal_signal)[0x8473d87]

[0xb7724400]

[0xb7724424]

/lib/i386-linux-gnu/libc.so.6(gsignal+0x4f)[0xb72001ef]

/lib/i386-linux-gnu/libc.so.6(abort+0x175)[0xb7203835]

/lib/i386-linux-gnu/libc.so.6(+0x27095)[0xb71f9095]

/lib/i386-linux-gnu/libc.so.6(+0x27147)[0xb71f9147]

sql/rpl_parallel.cc:1870(rpl_parallel_thread_pool::get_thread(rpl_parallel_thread**, rpl_parallel_entry*))[0x8402a37]

sql/rpl_parallel.cc:2012(rpl_parallel_entry::choose_thread(rpl_group_info*, bool*, PSI_stage_info_v1*, bool))[0x8402f58]

sql/rpl_parallel.cc:2543(rpl_parallel::do_event(rpl_group_info*, Log_event*, unsigned long long))[0x840414b]

sql/slave.cc:3581(exec_relay_log_event)[0x81e9613]

sql/slave.cc:4752(handle_slave_sql)[0x81ece54]

perfschema/pfs.cc:1862(pfs_spawn_thread)[0x863e698]

/lib/i386-linux-gnu/libpthread.so.0(+0x6d4c)[0xb76b3d4c]

/lib/i386-linux-gnu/libc.so.6(clone+0x5e)[0xb72bcace]

Trying to get some variables.

Some pointers may be invalid and cause the dump to abort.

Query (0x0): 

Connection ID (thread ID): 981

Status: NOT_KILLED