static struct regulator *create_regulator(struct regulator_dev *rdev,
					  struct device *dev,
					  const char *supply_name)
{
	struct regulator *regulator;
	char buf[REG_STR_SIZE];
	int err, size;

	regulator = kzalloc(sizeof(*regulator), GFP_KERNEL);
	if (regulator == NULL)
		return NULL;

	mutex_lock(&rdev->mutex);
	regulator->rdev = rdev;
	list_add(&regulator->list, &rdev->consumer_list);

	if (dev) {
		regulator->dev = dev;

		/* Add a link to the device sysfs entry */
		size = scnprintf(buf, REG_STR_SIZE, "%s-%s",
				 dev->kobj.name, supply_name);
		if (size >= REG_STR_SIZE)
			goto overflow_err;

		regulator->supply_name = kstrdup(buf, GFP_KERNEL);
		if (regulator->supply_name == NULL)
			goto overflow_err;

		err = sysfs_create_link(&rdev->dev.kobj, &dev->kobj,
					buf);
		if (err) {
			rdev_warn(rdev, "could not add device link %s err %d\n",
				  dev->kobj.name, err);
			/* non-fatal */
		}
	} else {
		regulator->supply_name = kstrdup(supply_name, GFP_KERNEL);
		if (regulator->supply_name == NULL)
			goto overflow_err;
	}

	regulator->debugfs = debugfs_create_dir(regulator->supply_name,
						rdev->debugfs);
	if (!regulator->debugfs) {
		rdev_warn(rdev, "Failed to create debugfs directory\n");
	} else {
		debugfs_create_u32("uA_load", 0444, regulator->debugfs,
				   &regulator->uA_load);
		debugfs_create_u32("min_uV", 0444, regulator->debugfs,
				   &regulator->min_uV);
		debugfs_create_u32("max_uV", 0444, regulator->debugfs,
				   &regulator->max_uV);
	}

	/*
	 * Check now if the regulator is an always on regulator - if
	 * it is then we don't need to do nearly so much work for
	 * enable/disable calls.
	 */
	if (!_regulator_can_change_status(rdev) &&
	    _regulator_is_enabled(rdev))
		regulator->always_on = true;

	mutex_unlock(&rdev->mutex);
	return regulator;
overflow_err:
	list_del(&regulator->list);
	kfree(regulator);
	mutex_unlock(&rdev->mutex);
	return NULL;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.