linux-kernel - Re: [PATCH RESEND] x86: consider effective protection attributes in W+X check

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Message-ID: <20180220081042.wgriecqneizg3df7@gmail.com>
Date:   Tue, 20 Feb 2018 09:10:42 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Jan Beulich <JBeulich@...e.com>
Cc:     mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND] x86: consider effective protection attributes in
 W+X check


* Jan Beulich <JBeulich@...e.com> wrote:

> Using just the leaf page table entry flags would cause a false warning
> in case _PAGE_RW is clear or _PAGE_NX is set in a higher level entry.

Under what circumstances did you see false positive warnings?

> Hand through both the current entry's flags as well as the accumulated
> effective value (the latter as pgprotval_t instead of pgprot_t, as it's
> not an actual entry's value).
> 
> Signed-off-by: Jan Beulich <jbeulich@...e.com>
> Reviewed-by: Juergen Gross <jgross@...e.com>
> ---
>  arch/x86/mm/dump_pagetables.c |   92 ++++++++++++++++++++++++++----------------
>  1 file changed, 57 insertions(+), 35 deletions(-)

Could you please rebase this on top of latest tip:master, which changed 
arch/x86/mm/dump_pagetables.c non-trivially due the dynamic 5 level paging 
changes?

Thanks,

	Ingo