rpl.rpl_gtid_basic, rpl.rpl_show_slave_hosts failed in buildbot

rpl.rpl_gtid_basic 'innodb_plugin,mix'   w2 [ fail ]

        Test ended at 2016-06-30 03:09:56

CURRENT_TEST: rpl.rpl_circular_for_4_hosts

mysqltest got signal 6

read_command_buf (0x334ba910): }nt_length)), 0))`

conn->name (0x1002394f7b8): server_4

Attempting backtrace...

stack_bottom = 0x0 thread_stack 0x3c000

/var/lib/buildbot/maria-slave/p8-trusty-bintar/build/client/mysqltest(my_print_stacktrace+0x64)[0x330fcee4]

/var/lib/buildbot/maria-slave/p8-trusty-bintar/build/client/mysqltest(+0x40ad8)[0x330a0ad8]

mysys/stacktrace.c:246(my_print_stacktrace)[0x3fff7a0f0478]

/opt/at8.0/lib64/power8/libpthread.so.0(recv+0x38)[0x3fff7a0c449c]

client/mysqltest.cc:8769(dump_backtrace)[0x100238e4a78]

vio/viosocket.c:172(vio_read)[0x330e5cdc]

vio/viosocket.c:226(vio_read_buff)[0x330e5f2c]

sql/net_serv.cc:873(my_real_read)[0x33105610]

sql/net_serv.cc:1100(my_net_read_packet)[0x33106acc]

sql-common/client.c:581(cli_safe_read)[0x330b808c]

sql-common/client.c:3990(cli_read_query_result)[0x330b9bc4]

libmysql/libmysql.c:4907(mysql_read_query_result)[0x330c8c10]

tests/nonblock-wrappers.h:360(wrap_mysql_read_query_result(st_mysql*))[0x330a1f74]

client/mysqltest.cc:7734(run_query_normal(st_connection*, st_command*, int, char*, int, st_dynamic_string*, st_dynamic_string*))[0x330b5e18]

client/mysqltest.cc:8497(run_query(st_connection*, st_command*, int))[0x330b6598]

client/mysqltest.cc:9277(main)[0x3309f52c]

/opt/at8.0/lib64/power8/libc.so.6(+0x22a00)[0x3fff799a2a00]

/opt/at8.0/lib64/power8/libc.so.6(__libc_start_main+0xc4)[0x3fff799a2c14]

Writing a core file...

CURRENT_TEST: rpl.rpl_gtid_basic

Failed to start mysqld.1

 - saving '/var/lib/buildbot/maria-slave/p8-trusty-bintar/build/mysql-test/var/2/log/rpl.rpl_gtid_basic-innodb_plugin,mix/' to '/var/lib/buildbot/maria-slave/p8-trusty-bintar/build/mysql-test/var/log/rpl.rpl_gtid_basic-innodb_plugin,mix/'