Re: [PATCH 5/8] x86, pkeys: allocation/free syscalls

From: Dave Hansen
Date: Wed Jun 01 2016 - 20:17:40 EST

On 06/01/2016 05:11 PM, Michael Kerrisk (man-pages) wrote:
>>> >>
>>> >> If I read this right, it doesn't actually remove any pkey restrictions
>>> >> that may have been applied while the key was allocated. So there could be
>>> >> pages with that key assigned that might do surprising things if the key is
>>> >> reallocated for another use later, right? Is that how the API is intended
>>> >> to work?
>> >
>> > Yeah, that's how it works.
>> >
>> > It's not ideal. It would be _best_ if we during mm_pkey_free(), we
>> > ensured that no VMAs under that mm have that vma_pkey() set. But, that
>> > search would be potentially expensive (a walk over all VMAs), or would
>> > force us to keep a data structure with a count of all the VMAs with a
>> > given key.
>> >
>> > I should probably discuss this behavior in the manpages and address it
> s/probably//
> And, did I miss it. Was there an updated man-pages patch in the latest
> series? I did not notice it.

There have been to changes to the patches that warranted updating the
manpages until now. I'll send the update immediately.