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=-13.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 6331FC432C0 for ; Tue, 3 Dec 2019 15:14:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1E7BA206EC for ; Tue, 3 Dec 2019 15:14:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HFzHI/nH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E7BA206EC 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 B0C6C6B0592; Tue, 3 Dec 2019 10:14:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id ABD666B0593; Tue, 3 Dec 2019 10:14:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 984EE6B0594; Tue, 3 Dec 2019 10:14:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0137.hostedemail.com [216.40.44.137]) by kanga.kvack.org (Postfix) with ESMTP id 82F656B0592 for ; Tue, 3 Dec 2019 10:14:31 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 1D0E0441E for ; Tue, 3 Dec 2019 15:14:31 +0000 (UTC) X-FDA: 76224176742.18.hen55_a46347fdba36 X-HE-Tag: hen55_a46347fdba36 X-Filterd-Recvd-Size: 5754 Received: from mail-wr1-f65.google.com (mail-wr1-f65.google.com [209.85.221.65]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Tue, 3 Dec 2019 15:14:30 +0000 (UTC) Received: by mail-wr1-f65.google.com with SMTP id z7so4051938wrl.13 for ; Tue, 03 Dec 2019 07:14:30 -0800 (PST) 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=dmOuXsafeZU3kIGHgzWIa3o5RYVAtIPmzaTqgn68fok=; b=HFzHI/nH0lzp59T9wfryKzfPu+7vHr+88xeBjdBKyLEiPrxltLaWbll73XthmXJYyS izpsaCINNDSNHAtSyEhxTtojHXpQx/MXwU1uumGl2xa79eOD6t7Nk17O/0pDATZ2Kyaa Ebs+As4m7DiVAXoStksINxEqqu6j/SvM0fPdhQXN1JbkUYWyPl/K7nZfQQgDyUDnemSI /t40YE4+mWSqXmsL4fc6VHhW4SrV44PzhD3mQ9UDA7OjlzJrvB/p64rH5n+xSspWIVMf jc6YsYYk+O96arEoPjXmEVyb8SN0XOx1q6gkWf32sFt6VbzaDZMBCI8TLA0SqRworKI8 OPrQ== 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=dmOuXsafeZU3kIGHgzWIa3o5RYVAtIPmzaTqgn68fok=; b=a11p3jvcbs2UdZQvvTknsLcunYHca14xyqY7pzpJrEQfxDMa/wQgdoJFlH4oRqy3Ct Ay22wGjxNtKJrvU1fYeVtRiC/UBKlDQV/xMyHvsohp7gE2nLlE9+1JATHLzZ3BkTWJQ5 dfR+onkhto5bPJCuYUv7bSCGM4fQ3QQNFytgxX/JXTSlavcNW8rWW0PQ2kPpS3rwEvHQ S6eQ1dOulFK7TwNq3Z5VSUDsNOuoLVHPCQ6ixB6Mt6djv7HobZM5lA3EwLQg9/hLH2Bl pRqMIWVa6Z7lrNg7ID5pSxwhgXlQgYhu565G5obpSZClpBnA+hJgo0gCo1o60fXxeBdy 34bQ== X-Gm-Message-State: APjAAAU8b5/BeHgJN74wOLdaAMAENp1ECYWLS7VyRCU9AMEtJG/RXAAC lUD/xVA+8an9kCzm5bIIwDVUCHdQxNyysG7m1b2pUw== X-Google-Smtp-Source: APXvYqxF+Bl4ERUKu1aYDmvtXeoXipisJcQh94gszeh0iJ761RKfhj1+4XllakikInGgAY4dK/IIKmJh7i9nfOs9hKo= X-Received: by 2002:a5d:6886:: with SMTP id h6mr5693825wru.154.1575386068819; Tue, 03 Dec 2019 07:14:28 -0800 (PST) MIME-Version: 1.0 References: <591B421C-F7AB-4394-83B5-AD3A86580C64@lca.pw> In-Reply-To: <591B421C-F7AB-4394-83B5-AD3A86580C64@lca.pw> From: Alexander Potapenko Date: Tue, 3 Dec 2019 16:14:17 +0100 Message-ID: Subject: Re: [PATCH RFC v3 18/36] kmsan: disable LOCK_DEBUGGING_SUPPORT To: Qian Cai Cc: Marco Elver , Eric Biggers , Christoph Hellwig , Herbert Xu , Harry Wentland , Vegard Nossum , Dmitry Vyukov , Linux Memory Management List , Al Viro , Andreas Dilger , Andrew Morton , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Thomas Gleixner , Vasily Gorbik , Wolfram Sang 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 Tue, Dec 3, 2019 at 4:00 PM Qian Cai wrote: > > > > > On Dec 3, 2019, at 9:35 AM, Alexander Potapenko wro= te: > > > > At this point I don't really know why KMSAN and lockdep don't play > > well together, but I'm not expecting anyone to use them together > > either. > > Of course people will use those together. For example, distro debug kerne= l variants. Some tools are just not designed to work together. For example, you won't be able to compile the kernel with both KASAN and KMSAN enabled at the same time. Lockdep doesn't require any instrumentation to work, so it _might_ be possible to make it work with KMSAN, but it will probably still slow down the things to an unacceptable level. I'm inclining towards disabling the two together for now, unless anyone is willing to address that issue. Please let me know if you think I need to keep the link to https://github.com/google/kmsan/issues/57 in the Kconfig comment, right now it looks like: # KMSAN is currently incompatible with lockdep. --=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