unit.conc_bulk1 fails in buildbot with LeakSanitizer: detected memory leaks

unit.conc_bulk1                          w1 [ fail ]

        Test ended at 2019-05-04 11:49:30

CURRENT_TEST: unit.conc_bulk1

# port: 16000

# socketname: /dev/shm/var/tmp/1/mysqld.1.sock

1..15

# Testing against MySQL Server 10.2.24-MariaDB-debug-log

# Host: Localhost via UNIX socket

# Client library: 10.2.24

# bulk supported

ok 1 - check_bulk

# waiting for server fix

ok 2 # skip test_mdev16593

ok 3 - bulk_null_null

ok 4 - test_char_conv1

ok 5 - test_char_conv2

ok 6 - test_conc243

# Bulk operation without parameters is not supported

ok 7 - update_no_param

# rows: 5

ok 8 - bulk5

ok 9 - bulk6

ok 10 - bulk1

ok 11 - bulk2

ok 12 - bulk3

ok 13 - bulk4

ok 14 - bulk_null

ok 15 - bulk_skip_row

# close default

==6237==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 7 byte(s) in 1 object(s) allocated from:

    #0 0x7f027762030f in strdup (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x6230f)

    #1 0x5570cf4ae716 in bulk_null /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/bulk1.c:320

    #2 0x5570cf4ac0a2 in run_tests /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/my_test.h:579

    #3 0x5570cf4b2e9d in main /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/bulk1.c:1095

    #4 0x7f027622482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

Direct leak of 4 byte(s) in 1 object(s) allocated from:

    #0 0x7f027762030f in strdup (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x6230f)

    #1 0x5570cf4ae6ce in bulk_null /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/bulk1.c:319

    #2 0x5570cf4ac0a2 in run_tests /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/my_test.h:579

    #3 0x5570cf4b2e9d in main /home/buildbot/buildbot/build/mariadb-10.2.24/libmariadb/unittest/libmariadb/bulk1.c:1095

    #4 0x7f027622482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

SUMMARY: AddressSanitizer: 11 byte(s) leaked in 2 allocation(s).