static int __ipmi_bmc_register(struct ipmi_smi *intf,
			       struct ipmi_device_id *id,
			       bool guid_set, guid_t *guid, int intf_num)
{
	int               rv;
	struct bmc_device *bmc;
	struct bmc_device *old_bmc;

	/*
	 * platform_device_register() can cause bmc_reg_mutex to
	 * be claimed because of the is_visible functions of
	 * the attributes.  Eliminate possible recursion and
	 * release the lock.
	 */
	intf->in_bmc_register = true;
	mutex_unlock(&intf->bmc_reg_mutex);

	/*
	 * Try to find if there is an bmc_device struct
	 * representing the interfaced BMC already
	 */
	mutex_lock(&ipmidriver_mutex);
	if (guid_set)
		old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, guid);
	else
		old_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,
						    id->product_id,
						    id->device_id);

	/*
	 * If there is already an bmc_device, free the new one,
	 * otherwise register the new BMC device
	 */
	if (old_bmc) {
		bmc = old_bmc;
		/*
		 * Note: old_bmc already has usecount incremented by
		 * the BMC find functions.
		 */
		intf->bmc = old_bmc;
		mutex_lock(&bmc->dyn_mutex);
		list_add_tail(&intf->bmc_link, &bmc->intfs);
		mutex_unlock(&bmc->dyn_mutex);

		dev_info(intf->si_dev,
			 "interfacing existing BMC (man_id: 0x%6.6x, prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
			 bmc->id.manufacturer_id,
			 bmc->id.product_id,
			 bmc->id.device_id);
	} else {
		bmc = kzalloc(sizeof(*bmc), GFP_KERNEL);
		if (!bmc) {
			rv = -ENOMEM;
			goto out;
		}
		INIT_LIST_HEAD(&bmc->intfs);
		mutex_init(&bmc->dyn_mutex);
		INIT_WORK(&bmc->remove_work, cleanup_bmc_work);

		bmc->id = *id;
		bmc->dyn_id_set = 1;
		bmc->dyn_guid_set = guid_set;
		bmc->guid = *guid;
		bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;

		bmc->pdev.name = "ipmi_bmc";

		rv = ida_simple_get(&ipmi_bmc_ida, 0, 0, GFP_KERNEL);
		if (rv < 0)
			goto out;
		bmc->pdev.dev.driver = &ipmidriver.driver;
		bmc->pdev.id = rv;
		bmc->pdev.dev.release = release_bmc_device;
		bmc->pdev.dev.type = &bmc_device_type;
		kref_init(&bmc->usecount);

		intf->bmc = bmc;
		mutex_lock(&bmc->dyn_mutex);
		list_add_tail(&intf->bmc_link, &bmc->intfs);
		mutex_unlock(&bmc->dyn_mutex);

		rv = platform_device_register(&bmc->pdev);
		if (rv) {
			dev_err(intf->si_dev,
				"Unable to register bmc device: %d\n",
				rv);
			goto out_list_del;
		}

		dev_info(intf->si_dev,
			 "Found new BMC (man_id: 0x%6.6x, prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
			 bmc->id.manufacturer_id,
			 bmc->id.product_id,
			 bmc->id.device_id);
	}

	/*
	 * create symlink from system interface device to bmc device
	 * and back.
	 */
	rv = sysfs_create_link(&intf->si_dev->kobj, &bmc->pdev.dev.kobj, "bmc");
	if (rv) {
		dev_err(intf->si_dev, "Unable to create bmc symlink: %d\n", rv);
		goto out_put_bmc;
	}

	if (intf_num == -1)
		intf_num = intf->intf_num;
	intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
	if (!intf->my_dev_name) {
		rv = -ENOMEM;
		dev_err(intf->si_dev, "Unable to allocate link from BMC: %d\n",
			rv);
		goto out_unlink1;
	}

	rv = sysfs_create_link(&bmc->pdev.dev.kobj, &intf->si_dev->kobj,
			       intf->my_dev_name);
	if (rv) {
		kfree(intf->my_dev_name);
		intf->my_dev_name = NULL;
		dev_err(intf->si_dev, "Unable to create symlink to bmc: %d\n",
			rv);
		goto out_free_my_dev_name;
	}

	intf->bmc_registered = true;

out:
	mutex_unlock(&ipmidriver_mutex);
	mutex_lock(&intf->bmc_reg_mutex);
	intf->in_bmc_register = false;
	return rv;


out_free_my_dev_name:
	kfree(intf->my_dev_name);
	intf->my_dev_name = NULL;

out_unlink1:
	sysfs_remove_link(&intf->si_dev->kobj, "bmc");

out_put_bmc:
	mutex_lock(&bmc->dyn_mutex);
	list_del(&intf->bmc_link);
	mutex_unlock(&bmc->dyn_mutex);
	intf->bmc = &intf->tmp_bmc;
	kref_put(&bmc->usecount, cleanup_bmc_device);
	goto out;

out_list_del:
	mutex_lock(&bmc->dyn_mutex);
	list_del(&intf->bmc_link);
	mutex_unlock(&bmc->dyn_mutex);
	intf->bmc = &intf->tmp_bmc;
	put_device(&bmc->pdev.dev);
	goto out;
}

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.