From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id 249156B79A9 for ; Thu, 6 Sep 2018 12:40:05 -0400 (EDT) Received: by mail-pl1-f200.google.com with SMTP id bh1-v6so5752388plb.15 for ; Thu, 06 Sep 2018 09:40:05 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a66-v6sor1367213pla.133.2018.09.06.09.40.03 for (Google Transport Security); Thu, 06 Sep 2018 09:40:03 -0700 (PDT) MIME-Version: 1.0 References: <20180905141032.b1ddaab53d1b2b3bada95415@linux-foundation.org> <20180906100543.GI3592@arm.com> In-Reply-To: From: Nick Desaulniers Date: Thu, 6 Sep 2018 09:39:51 -0700 Message-ID: Subject: Re: [PATCH v6 00/18] khwasan: kernel hardware assisted address sanitizer Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Konovalov Cc: Will Deacon , Andrew Morton , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Catalin Marinas , Christoph Lameter , Mark Rutland , Marc Zyngier , Dave Martin , Ard Biesheuvel , "Eric W . Biederman" , Ingo Molnar , Paul Lawrence , Geert Uytterhoeven , Arnd Bergmann , "Kirill A . Shutemov" , Greg KH , Kate Stewart , Mike Rapoport , kasan-dev , linux-doc@vger.kernel.org, LKML , Linux ARM , linux-sparse@vger.kernel.org, Linux Memory Management List , Linux Kbuild mailing list , Kostya Serebryany , Evgenii Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Jann Horn , Mark Brand , Chintan Pandya , Vishwath Mohan On Thu, Sep 6, 2018 at 4:06 AM Andrey Konovalov wrote: > > On Thu, Sep 6, 2018 at 12:05 PM, Will Deacon wrote: > > On Wed, Sep 05, 2018 at 02:10:32PM -0700, Andrew Morton wrote: > >> On Wed, 29 Aug 2018 13:35:04 +0200 Andrey Konovalov wrote: > >> > >> > This patchset adds a new mode to KASAN [1], which is called KHWASAN > >> > (Kernel HardWare assisted Address SANitizer). > >> > >> We're at v6 and there are no reviewed-by's or acked-by's to be seen. > >> Is that a fair commentary on what has been happening, or have people > >> been remiss in sending and gathering such things? > > > > I still have concerns about the consequences of merging this as anything > > other than a debug option [1]. Unfortunately, merging it as a debug option > > defeats the whole point, so I think we need to spend more effort on developing > > tools that can help us to find and fix the subtle bugs which will arise from > > enabling tagged pointers in the kernel. > > I totally don't mind calling it a debug option. Do I need to somehow > specify it somewhere? > > Why does it defeat the point? The point is to ease KASAN-like testing > on devices with limited memory. I don't disagree with using it strictly for debug. When I say I want the series for Pixel phones, I should have been clearer that my intent is for a limited pool of internal testers to walk around with KHWASAN enabled devices; not general end users. It's hard enough today to get anyone to test KASAN/ASAN on their "daily driver" due to the memory usage and resulting performance. We don't ship KASAN or KUBSAN on by default to end users (nor plan to); it's used strictly for fuzzing through syzkaller (or by brave "dogfooders" on the internal kernel teams). KHWASAN would let these dogfooders go from being brave to fearless. -- Thanks, ~Nick Desaulniers