From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA154C43331 for ; Wed, 25 Mar 2020 11:04:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7C0E82077D for ; Wed, 25 Mar 2020 11:04:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LZNkXvNl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C0E82077D Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1B0E46B006C; Wed, 25 Mar 2020 07:04:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 187946B006E; Wed, 25 Mar 2020 07:04:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 076836B0071; Wed, 25 Mar 2020 07:04:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0191.hostedemail.com [216.40.44.191]) by kanga.kvack.org (Postfix) with ESMTP id E69216B006C for ; Wed, 25 Mar 2020 07:04:38 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A38EB180AD806 for ; Wed, 25 Mar 2020 11:04:38 +0000 (UTC) X-FDA: 76633601436.17.wash10_287ccaa67aa03 X-HE-Tag: wash10_287ccaa67aa03 X-Filterd-Recvd-Size: 6371 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Wed, 25 Mar 2020 11:04:38 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id 65so2487057wrl.1 for ; Wed, 25 Mar 2020 04:04:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=fzM0gvNDgDOrLOPF7RVKmTb1NyX/hVynml0P5LCBH74=; b=LZNkXvNlY+qH0T/KZJPtGxxr3V6IysIabdl+WmH8tMemBFiltmAwf5B99Go+zWIA0A QBz5r8yBDLdKCIYaaXHPvs49BaR8zGi1olctYMS0MOluI3717/IDQHURFqMuQ/yZDF4c sRGL4aEbdAG5f5/LOjO4tbv+uQKzlOnU4EgSENvo42YK4B8MelDnkPxnu6vEd9KZCGHa 8qVxpFjfPz1aH7XrtNrsUrZZyYsJ6ia9JPYCP1gME3ptGb5/H6A+o1B4pH+UAzfxkDTT 8Atn1K1r6nbEuFIvjIyC9OGqZVV2pVAwCGLkYwFD/odjvUWMSOXK+lk4Vur0UIQRHdYo +vbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=fzM0gvNDgDOrLOPF7RVKmTb1NyX/hVynml0P5LCBH74=; b=rXAm0zaqdEwNABgUh57enA8W5o+N+1kAiqhghXnPVgHQkzJnVU+YQU8w4mlof8ry85 42TvCnT87PYkaif2F1IxPioAYHoQRwgwHKGvQQ8FLfjUeB2hn+amUwxCBBDIOi4LTQ6/ J0NAw8nmvK1/rLYrSYEsHHWMFa1kWdRKhQvOVqMiKRDPFb3TKxEq7LCuj0ux1n1CaEcn tElG/1atQLqFqG5vZq+tYXINQWbfqmscZFfOCEA7G9lprRGhhObRRiMHI2ZhBSY60QNC HUWN4wou3rqh14Ibz6rO5wikFc8lNAM/qOHqOx58OOWVJEvzIUxJKUka7ATyHQE6giE+ I1WA== X-Gm-Message-State: ANhLgQ1LYZCmDkxHTkMCKYLA/Ry7YKT7seJRarv0pWWjHN+gy0Bx2s3h E/wua8X43SnGdz2eE4YGMA7rVbzsdSC38yLKvOrqdA== X-Google-Smtp-Source: ADFU+vum/Eqvj5Ltn4HpY+WQbajUs9qyHH6WbtJxu4uwkWQHOM8E0SUAGYsdqeFnSYN3Q1hVxWamllu1y10eDS2eZ+0= X-Received: by 2002:a5d:4b08:: with SMTP id v8mr2835055wrq.200.1585134276306; Wed, 25 Mar 2020 04:04:36 -0700 (PDT) MIME-Version: 1.0 References: <20191220184955.223741-1-glider@google.com> <20191223075141.GK13335@unreal> <878smg385m.fsf@nanos.tec.linutronix.de> In-Reply-To: <878smg385m.fsf@nanos.tec.linutronix.de> From: Alexander Potapenko Date: Wed, 25 Mar 2020 12:04:24 +0100 Message-ID: Subject: Re: [PATCH RFC v4 00/42] Add KernelMemorySanitizer infrastructure To: Thomas Gleixner Cc: Leon Romanovsky , Alexander Viro , Andreas Dilger , Andrew Morton , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Dmitry Vyukov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Marco Elver , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Vasily Gorbik , Vegard Nossum , Wolfram Sang , Linux Memory Management List , Michal Hocko Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jan 9, 2020 at 5:30 PM Thomas Gleixner wrote: > > Alexander Potapenko writes: > >> > 2. checkpatch.pl complains a lot about the use of BUG_ON in KMSAN > >> > source. I don't have a strong opinion on this, but KMSAN is a debugg= ing > >> > tool, so any runtime invariant violation in it renders the tool usel= ess. > >> > Therefore it doesn't make much sense to not terminate after a bug in > >> > KMSAN. > >> > >> Such early termination will cause hard time for verification teams > >> execute any major test suite with KMSAN till it will be without any bu= gs. > >> So yes, I think that the best solution is to avoid BUG_ONs in non-crit= ical code. > >> > > > > To clarify, these BUG_ONs are for bugs in KMSAN itself. KMSAN reports > > don't provoke a BUG(), so many of them can be reported at once. > > Proceeding after a bug in the debugging tool itself might be a bad > > idea - any broken invariant denotes that all following reports may be > > incorrect. > > Correct, unless you can gracefully disable the debugging tool and just > continue which would be the best solution. (sorry for not responding earlier) Not sure gracefully disabling the tool and continuing will add any extra va= lue. In the case KMSAN is used for continuous testing it's important to fail early, so that the developers are aware that the tool is not testing anything. Pretending it still works and proceeding with execution may give us false sense of good testing coverage. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg