int bsg_register_queue(struct request_queue *q, struct device *parent,
		       const char *name, void (*release)(struct device *))
{
	struct bsg_class_device *bcd;
	dev_t dev;
	int ret;
	struct device *class_dev = NULL;
	const char *devname;

	if (name)
		devname = name;
	else
		devname = dev_name(parent);

	/*
	 * we need a proper transport to send commands, not a stacked device
	 */
	if (!queue_is_rq_based(q))
		return 0;

	bcd = &q->bsg_dev;
	memset(bcd, 0, sizeof(*bcd));

	mutex_lock(&bsg_mutex);

	ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
	if (ret < 0) {
		if (ret == -ENOSPC) {
			printk(KERN_ERR "bsg: too many bsg devices\n");
			ret = -EINVAL;
		}
		goto unlock;
	}

	bcd->minor = ret;
	bcd->queue = q;
	bcd->parent = get_device(parent);
	bcd->release = release;
	kref_init(&bcd->ref);
	dev = MKDEV(bsg_major, bcd->minor);
	class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
	if (IS_ERR(class_dev)) {
		ret = PTR_ERR(class_dev);
		goto put_dev;
	}
	bcd->class_dev = class_dev;

	if (q->kobj.sd) {
		ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
		if (ret)
			goto unregister_class_dev;
	}

	mutex_unlock(&bsg_mutex);
	return 0;

unregister_class_dev:
	device_unregister(class_dev);
put_dev:
	put_device(parent);
	idr_remove(&bsg_minor_idr, bcd->minor);
unlock:
	mutex_unlock(&bsg_mutex);
	return ret;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.