static int __send_empty_flush(struct clone_info *ci)
{
	unsigned target_nr = 0;
	struct dm_target *ti;

	BUG_ON(bio_has_data(ci->bio));
	while ((ti = dm_table_get_target(ci->map, target_nr++)))
		__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);

	return 0;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.