From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v15 00/17] arm64: untag user pointers passed to the kernel
Date: Wed, 22 May 2019 12:21:27 -0700
Message-ID: <201905221157.A9BAB1F296@keescook>
References: <cover.1557160186.git.andreyknvl@google.com>
 <20190517144931.GA56186@arrakis.emea.arm.com>
 <CAFKCwrj6JEtp4BzhqO178LFJepmepoMx=G+YdC8sqZ3bcBp3EQ@mail.gmail.com>
 <20190521182932.sm4vxweuwo5ermyd@mbp>
 <201905211633.6C0BF0C2@keescook>
 <20190522101110.m2stmpaj7seezveq@mbp>
 <CAJgzZoosKBwqXRyA6fb8QQSZXFqfHqe9qO9je5TogHhzuoGXJQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
Return-path: <dri-devel-bounces@lists.freedesktop.org>
Content-Disposition: inline
In-Reply-To: <CAJgzZoosKBwqXRyA6fb8QQSZXFqfHqe9qO9je5TogHhzuoGXJQ@mail.gmail.com>
List-Unsubscribe: <https://lists.freedesktop.org/mailman/options/dri-devel>,
 <mailto:dri-devel-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <https://lists.freedesktop.org/archives/dri-devel>
List-Post: <mailto:dri-devel@lists.freedesktop.org>
List-Help: <mailto:dri-devel-request@lists.freedesktop.org?subject=help>
List-Subscribe: <https://lists.freedesktop.org/mailman/listinfo/dri-devel>,
 <mailto:dri-devel-request@lists.freedesktop.org?subject=subscribe>
Errors-To: dri-devel-bounces@lists.freedesktop.org
Sender: "dri-devel" <dri-devel-bounces@lists.freedesktop.org>
To: enh <enh@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>, kvm@vger.kernel.org, Szabolcs Nagy <Szabolcs.Nagy@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, dri-devel@lists.freedesktop.org, Linux Memory Management List <linux-mm@kvack.org>, Khalid Aziz <khalid.aziz@oracle.com>, "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@vger.kernel.org>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Jacob Bramley <Jacob.Bramley@arm.com>, Leon Romanovsky <leon@kernel.org>, linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Dmitry Vyukov <dvyukov@google.com>, Dave Martin <Dave.Martin@arm.com>, Evgenii Stepanov <eugenis@google.com>, linux-media@vger.kernel.org, Kevin Brodsky <kevin.brodsky@arm.com>, Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>, Andrey Konovalov <andreyknvl@google.com>, Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>, Alex
List-Id: linux-rdma@vger.kernel.org
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