Re: [PATCH 26/26] x86, pkeys: Documentation

From: Linus Torvalds
Date: Thu Oct 01 2015 - 18:48:52 EST


On Thu, Oct 1, 2015 at 6:33 PM, Dave Hansen <dave@xxxxxxxx> wrote:
>
> Here it is in a quite fugly form (well, it's not opt-in). Init crashes
> if I boot with this, though.
>
> I'll see if I can turn it in to a bit more of an opt-in and see what's
> actually going wrong.

It's quite likely that you will find that compilers put read-only
constants in the text section, knowing that executable means readable.

So it's entirely possible that it's pretty much all over.

That said, I don't understand your patch. Why check PROT_WRITE? We've
had :"execute but not write" forever. It's "execute and not *read*"
that is interesting.

So I wonder if your testing is just bogus. But maybe I'm mis-reading this?

Linus
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