Assertion failure 'slot != NULL' in os_aio_linux_collect() during main.index_merge_innodb

main.index_merge_innodb 'xtradb'         w2 [ fail ]

        Test ended at 2017-10-24 20:53:56

CURRENT_TEST: main.index_merge_innodb

mysqltest: At line 66: query 'INSERT INTO t1(a,b) SELECT a,b FROM t1' failed: 2013: Lost connection to MySQL server during query

…

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

2017-10-24 20:53:56 7fdac6ba6700  InnoDB: Assertion failure in thread 140577613702912 in file os0file.cc line 5128

InnoDB: Failing assertion: slot != NULL

	/* Initialize the events. The timeout value is arbitrary.

	We probably need to experiment with it a little. */

	memset(events, 0, sizeof(*events) * seg_size);

	timeout.tv_sec = 0;

	timeout.tv_nsec = OS_AIO_REAP_TIMEOUT;

	ret = io_getevents(io_ctx, 1, seg_size, events, &timeout);

	if (ret > 0) {

		for (i = 0; i < ret; i++) {

			os_aio_slot_t*	slot;

			struct iocb*	control;

			control = (struct iocb*) events[i].obj;

			ut_a(control != NULL);

			slot = (os_aio_slot_t*) control->data;

			/* Some sanity checks. */

			ut_a(slot != NULL);