_xfs_buf_alloc(
	struct xfs_buftarg	*target,
	struct xfs_buf_map	*map,
	int			nmaps,
	xfs_buf_flags_t		flags)
{
	struct xfs_buf		*bp;
	int			error;
	int			i;

	bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS);
	if (unlikely(!bp))
		return NULL;

	/*
	 * We don't want certain flags to appear in b_flags unless they are
	 * specifically set by later operations on the buffer.
	 */
	flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);

	atomic_set(&bp->b_hold, 1);
	atomic_set(&bp->b_lru_ref, 1);
	init_completion(&bp->b_iowait);
	INIT_LIST_HEAD(&bp->b_lru);
	INIT_LIST_HEAD(&bp->b_list);
	RB_CLEAR_NODE(&bp->b_rbnode);
	sema_init(&bp->b_sema, 0); /* held, no waiters */
	XB_SET_OWNER(bp);
	bp->b_target = target;
	bp->b_flags = flags;

	/*
	 * Set length and io_length to the same value initially.
	 * I/O routines should use io_length, which will be the same in
	 * most cases but may be reset (e.g. XFS recovery).
	 */
	error = xfs_buf_get_maps(bp, nmaps);
	if (error)  {
		kmem_zone_free(xfs_buf_zone, bp);
		return NULL;
	}

	bp->b_bn = map[0].bm_bn;
	bp->b_length = 0;
	for (i = 0; i < nmaps; i++) {
		bp->b_maps[i].bm_bn = map[i].bm_bn;
		bp->b_maps[i].bm_len = map[i].bm_len;
		bp->b_length += map[i].bm_len;
	}
	bp->b_io_length = bp->b_length;

	atomic_set(&bp->b_pin_count, 0);
	init_waitqueue_head(&bp->b_waiters);

	XFS_STATS_INC(xb_create);
	trace_xfs_buf_init(bp, _RET_IP_);

	return bp;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.