static void dm_wq_work(struct work_struct *work)
{
	struct mapped_device *md = container_of(work, struct mapped_device,
						work);
	struct bio *c;
	int srcu_idx;
	struct dm_table *map;

	map = dm_get_live_table(md, &srcu_idx);

	while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
		spin_lock_irq(&md->deferred_lock);
		c = bio_list_pop(&md->deferred);
		spin_unlock_irq(&md->deferred_lock);

		if (!c)
			break;

		if (dm_request_based(md))
			generic_make_request(c);
		else
			__split_and_process_bio(md, map, c);
	}

	dm_put_live_table(md, srcu_idx);
}

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.