Re: [PATCH v2 2/4] fs/proc/task_mmu: Implement IOCTL to get and clear soft dirty PTE bit

Greg KH
2022-08-25T07:22:58Z

On Thu, Aug 25, 2022 at 12:09:24PM +0500, Muhammad Usama Anjum wrote:
> - The flags can be specified in the flags field. Currently only one
> PAGEMAP_SD_NO_REUSED_REGIONS is supported which can be specified to
> ignore the VMA dirty flags.

You forgot to check that all other bits in that flag are set to 0
properly, otherwise you can never add a new bit to the field ever as you
can't expect userspace got it right and did not accidentaly set it
already.

There is kernel documentation on how to add a new ioctl, you might want
to read up on that first before resending this.

thanks,

greg k-h