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

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 26/26] x86, pkeys: Documentation
Date	2015-10-02 00:50 +0200
Message-ID	<qeUPL-1B8-5@gated-at.bofh.it> (permalink)
References	(4 earlier) <qcbtN-7ST-37@gated-at.bofh.it> <qckdI-3Kz-5@gated-at.bofh.it> <qeK42-2oH-7@gated-at.bofh.it> <qeSNY-71t-25@gated-at.bofh.it> <qeUG5-1pD-3@gated-at.bofh.it>
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On Thu, Oct 1, 2015 at 6:33 PM, Dave Hansen <dave@sr71.net> 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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Thread

Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-09-24 12:00 +0200
  Re: [PATCH 26/26] x86, pkeys: Documentation Andy Lutomirski <luto@amacapital.net> - 2015-09-24 21:20 +0200
    Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-09-25 09:20 +0200
  Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-09-24 21:20 +0200
    Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-09-25 08:20 +0200
    Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-01 13:20 +0200
      Re: [PATCH 26/26] x86, pkeys: Documentation Kees Cook <keescook@google.com> - 2015-10-01 22:40 +0200
        Re: [PATCH 26/26] x86, pkeys: Documentation Andy Lutomirski <luto@amacapital.net> - 2015-10-01 22:50 +0200
          Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-02 08:30 +0200
            Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-02 20:00 +0200
              Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-03 09:30 +0200
        Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-01 23:00 +0200
        Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-02 00:40 +0200
        Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-02 00:40 +0200
          Re: [PATCH 26/26] x86, pkeys: Documentation Kees Cook <keescook@google.com> - 2015-10-02 00:40 +0200
          Re: [PATCH 26/26] x86, pkeys: Documentation Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-02 00:50 +0200
            Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-02 01:00 +0200
              Re: [PATCH 26/26] x86, pkeys: Documentation Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-02 03:40 +0200
                Re: [PATCH 26/26] x86, pkeys: Documentation Dave Hansen <dave@sr71.net> - 2015-10-02 20:10 +0200
            Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-02 09:10 +0200
              Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-03 09:00 +0200
            Re: [PATCH 26/26] x86, pkeys: Documentation Paolo Bonzini <pbonzini@redhat.com> - 2015-10-02 13:50 +0200
              Re: [PATCH 26/26] x86, pkeys: Documentation Linus Torvalds <torvalds@linux-foundation.org> - 2015-10-02 14:00 +0200
                Re: [PATCH 26/26] x86, pkeys: Documentation Paolo Bonzini <pbonzini@redhat.com> - 2015-10-02 14:20 +0200
                Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-03 08:50 +0200
          Re: [PATCH 26/26] x86, pkeys: Documentation Andy Lutomirski <luto@amacapital.net> - 2015-10-02 01:00 +0200
          Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-02 08:10 +0200
  Re: [PATCH 26/26] x86, pkeys: Documentation Ingo Molnar <mingo@kernel.org> - 2015-10-03 10:20 +0200

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