tokudb.change_column_char failed in buildbot with Lost connection

tokudb.change_column_char                w2 [ fail ]

        Test ended at 2017-04-25 08:34:26

CURRENT_TEST: tokudb.change_column_char

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

included from /mnt/buildbot/build/mariadb-10.0.31/storage/tokudb/mysql-test/tokudb/t/change_column_char.test at line 4945:

At line 70: query 'if (`SELECT LOCATE(',', '$diff_tables') = 0`)

{' failed: 2013: Lost connection to MySQL server during query

The result from queries just before the failure was:

< snip >

CREATE TABLE ti LIKE t;

ALTER TABLE ti ENGINE=myisam;

INSERT INTO ti SELECT * FROM t;

ALTER TABLE ti CHANGE COLUMN a a CHAR(107);

ALTER TABLE t CHANGE COLUMN a a CHAR(107);

include/diff_tables.inc [test.t, test.ti]

DROP TABLE ti;

CREATE TABLE ti LIKE t;

ALTER TABLE ti ENGINE=myisam;

INSERT INTO ti SELECT * FROM t;

ALTER TABLE ti CHANGE COLUMN a a CHAR(108);

ALTER TABLE t CHANGE COLUMN a a CHAR(108);

include/diff_tables.inc [test.t, test.ti]

DROP TABLE ti;

CREATE TABLE ti LIKE t;

ALTER TABLE ti ENGINE=myisam;

INSERT INTO ti SELECT * FROM t;

ALTER TABLE ti CHANGE COLUMN a a CHAR(109);

ALTER TABLE t CHANGE COLUMN a a CHAR(109);

include/diff_tables.inc [test.t, test.ti]

More results from queries before failure can be found in /mnt/buildbot/build/mariadb-10.0.31/mysql-test/var/2/log/change_column_char.log

Server [mysqld.1 - pid: 21030, winpid: 21030, exit: 256] failed during test run

Server log from this test:

----------SERVER LOG START-----------

----------SERVER LOG END-------------