static int do_req_filebacked(struct loop_device *lo, struct request *rq)
{
	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
	loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;

	/*
	 * lo_write_simple and lo_read_simple should have been covered
	 * by io submit style function like lo_rw_aio(), one blocker
	 * is that lo_read_simple() need to call flush_dcache_page after
	 * the page is written from kernel, and it isn't easy to handle
	 * this in io submit style function which submits all segments
	 * of the req at one time. And direct read IO doesn't need to
	 * run flush_dcache_page().
	 */
	switch (req_op(rq)) {
	case REQ_OP_FLUSH:
		return lo_req_flush(lo, rq);
	case REQ_OP_DISCARD:
	case REQ_OP_WRITE_ZEROES:
		return lo_discard(lo, rq, pos);
	case REQ_OP_WRITE:
		if (lo->transfer)
			return lo_write_transfer(lo, rq, pos);
		else if (cmd->use_aio)
			return lo_rw_aio(lo, cmd, pos, WRITE);
		else
			return lo_write_simple(lo, rq, pos);
	case REQ_OP_READ:
		if (lo->transfer)
			return lo_read_transfer(lo, rq, pos);
		else if (cmd->use_aio)
			return lo_rw_aio(lo, cmd, pos, READ);
		else
			return lo_read_simple(lo, rq, pos);
	default:
		WARN_ON_ONCE(1);
		return -EIO;
		break;
	}
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.