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