In the Linux kernel, the following vulnerability has been resolved: block: Fix the maximum minor value is blkallocextminor() idaallocrange(..., min, max, ...) returns values from min to max, inclusive. So, NREXTDEVT is a valid idx returned by blkallocextminor(). This is an issue because in deviceadddisk(), this value is used in: ddev->devt = MKDEV(disk->major, disk->firstminor); and NREXTDEVT is '(1 << MINORBITS)'. So, should 'disk->firstminor' be NREXTDEVT, it would overflow.