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Date:   Wed, 8 Aug 2018 08:54:37 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Juergen Gross <jgross@...e.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>, Jiri Kosina <jkosina@...e.cz>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Brian Gerst <brgerst@...il.com>,
        David Laight <David.Laight@...lab.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        Eduardo Valentin <eduval@...zon.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Will Deacon <will.deacon@....com>, aliguori@...zon.com,
        daniel.gruss@...k.tugraz.at, hughd@...gle.com, keescook@...gle.com,
        Andrea Arcangeli <aarcange@...hat.com>,
        Waiman Long <llong@...hat.com>, Pavel Machek <pavel@....cz>,
        "David H . Gutteridge" <dhgutteridge@...patico.ca>, jroedel@...e.de
Subject: Re: [PATCH] x86/mm/pti: Move user W+X check into pti_finalize()

On 08/08/2018 04:16 AM, Joerg Roedel wrote:
> But with CONFIG_DEBUG_WX enabled, the user page-table is
> already checked in mark_readonly() for insecure mappings.
> This causes false-positive warnings, because the user
> page-table did not get the updated mappings yet.

One bit of information missing from the changelog: Could you clarify how
there are any entries in the user page tables for the code to complain?
Before pti_init(), I would have expected the user page tables to be empty.

That causes a different problem, but it would not have resulted in
warnings, so I think I'm missing something.

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