int vfio_pci_register_dev_region(struct vfio_pci_device *vdev,
				 unsigned int type, unsigned int subtype,
				 const struct vfio_pci_regops *ops,
				 size_t size, u32 flags, void *data)
{
	struct vfio_pci_region *region;

	region = krealloc(vdev->region,
			  (vdev->num_regions + 1) * sizeof(*region),
			  GFP_KERNEL);
	if (!region)
		return -ENOMEM;

	vdev->region = region;
	vdev->region[vdev->num_regions].type = type;
	vdev->region[vdev->num_regions].subtype = subtype;
	vdev->region[vdev->num_regions].ops = ops;
	vdev->region[vdev->num_regions].size = size;
	vdev->region[vdev->num_regions].flags = flags;
	vdev->region[vdev->num_regions].data = data;

	vdev->num_regions++;

	return 0;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.