mariabackup.data_directory, mariabackup.partial_exclude failed in buildbot with error on exec

mariabackup.data_directory               w4 [ fail ]

        Test ended at 2018-01-10 17:37:01

CURRENT_TEST: mariabackup.data_directory

mysqltest: At line 9: exec of '/usr/bin/mariabackup --defaults-file=/dev/shm/var/4/my.cnf --backup --target-dir=/dev/shm/var/4/tmp/backup 2>&1' failed, error: 256, status: 1, errno: 11

Output from before failure:

180110 17:37:01 Connecting to MySQL server host: localhost, user: root, password: set, port: 16040, socket: /dev/shm/var/tmp/4/mysqld.1.sock

Using server version 10.2.13-MariaDB-10.2.13+maria~xenial-log

/usr/bin/mariabackup based on MariaDB server 10.2.13-MariaDB debian-linux-gnu (i686) 

mariabackup: uses posix_fadvise().

mariabackup: cd to /dev/shm/var/4/mysqld.1/data/

mariabackup: open files limit requested 1024, set to 1024

mariabackup: using the following InnoDB configuration:

mariabackup:   innodb_data_home_dir = .

mariabackup:   innodb_data_file_path = ibdata1:12M:autoextend

mariabackup:   innodb_log_group_home_dir = ./

2018-01-10 17:37:01 3068790720 [Note] InnoDB: Number of pools: 1

180110 17:37:01 >> log scanned up to (1656143)

2018-01-10 17:37:01 3068790720 [Note] InnoDB: Log sequence number at the start 1637250 and the end 1652116 do not match

2018-01-10 17:37:01 3068790720 [ERROR] InnoDB: Checksum mismatch in datafile: ./ibdata1, Space ID:0, Flags: 0. Please refer to http://dev.mysql.com/doc/refman/5.7/en/innodb-troubleshooting-datadict.html for how to resolve the issue.

2018-01-10 17:37:01 3068790720 [Note] InnoDB: Restoring page [page id: space=0, page number=0] of datafile './ibdata1' from the doublewrite buffer. Writing 16384 bytes into file './ibdata1'

2018-01-10 17:37:01 3068790720 [Warning] InnoDB: Retry attempts for writing partial data failed.

2018-01-10 17:37:01 3068790720 [ERROR] InnoDB: Write to file ./ibdata1failed at offset 0, 16384 bytes should have been written, only 0 were written. Operating system error number 9. Check that your OS and file system support files of this size. Check also that the disk is not full or a disk quota exceeded.

2018-01-10 17:37:01 3068790720 [ERROR] InnoDB: Error number 9 means 'Bad file descriptor'

2018-01-10 17:37:01 3068790720 [Note] InnoDB: Some operating system error numbers are described at https://mariadb.com/kb/en/library/operating-system-error-codes/

mariabackup: Could not open or create data files.

mariabackup: If you tried to add new data files, and it failed here,

mariabackup: you should now edit innodb_data_file_path in my.cnf back

mariabackup: to what it was, and remove the new ibdata files InnoDB created

mariabackup: in this failed attempt. InnoDB only wrote those files full of

mariabackup: zeros, but did not yet use them in any way. But be careful: do not

mariabackup: remove old data files which contain your precious data!

mariabackup: error: xb_load_tablespaces() failed witherror code 39

mariabackup: Stopping log copying thread.

.

The result from queries just before the failure was:

CREATE TABLE t(a INT) ENGINE=InnoDB DATA DIRECTORY='table_data_dir';

INSERT INTO t VALUES(1);

# xtrabackup backup

 - saving '/dev/shm/var/4/log/mariabackup.data_directory/' to '/dev/shm/var/log/mariabackup.data_directory/'

Retrying test mariabackup.data_directory, attempt(2/3)...

worker[4] > Restart  - not started