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 8B428C2BBE2 for ; Wed, 4 Dec 2019 08:41:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4BC2C207DD for ; Wed, 4 Dec 2019 08:41:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OVHeWsvi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4BC2C207DD 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 C925C6B09A4; Wed, 4 Dec 2019 03:41:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C43786B09A5; Wed, 4 Dec 2019 03:41:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B31F26B09A6; Wed, 4 Dec 2019 03:41:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0108.hostedemail.com [216.40.44.108]) by kanga.kvack.org (Postfix) with ESMTP id 9DDEF6B09A4 for ; Wed, 4 Dec 2019 03:41:29 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 3D4E7180AD81F for ; Wed, 4 Dec 2019 08:41:29 +0000 (UTC) X-FDA: 76226815098.17.fang66_814e3145d0b4b X-HE-Tag: fang66_814e3145d0b4b X-Filterd-Recvd-Size: 6998 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Dec 2019 08:41:28 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id q10so7397491wrm.11 for ; Wed, 04 Dec 2019 00:41:28 -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=1t/SwJuJHDggU1hqNg9JY7u9PO44I81AU9wJuY4Gqlk=; b=OVHeWsvio5OyidVqGPJfSiT6KUSIqNzwp3QBhMoLidjvlClYCgWkrxeDYsiJxeZiHB +UgsBtXIW58feNzn6f5gQ+S/vTs74T+cUnfzvvUJ5If09EeP0tp764ADScnQ2MbrclW7 cN/Cci9Wn02FM6k8MkyVIeCwSLWGC5jb1sQhmGYnIYJRTvqJ9iG37QiDUGZvDdrwX3Kw q+wRQ0kOyNAUa/3NC7lXZlNESPLBBeZNwWabBF5g/qhpCkXpJEDhULYJTfEHTrTBqvVc bopmNjNOlOsh8MQDzCie/QlNwRqF1FUjZKWncI5Z0JleYQ2Jun4XCXJJTd8LYwGKd59Z 1Oaw== 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=1t/SwJuJHDggU1hqNg9JY7u9PO44I81AU9wJuY4Gqlk=; b=ct7ReNTtF0bHVKCtx1W4rqWk3HVVk7tUsJRDwZjjBgU3buwFp8NoK+8Q5pogBBsY/W RujDxMTJ4zDJ9RTUwpukMss6bJMH4edaV1qFnbpLvIUzQHKJscR3g1yqi/HpUV7i5iPH snByrOhQmdrTm6ah1ZpjmJFluiKVyV8//OjaN66sMsX8JIWMYRn1mZedhlWLnnBxEwv2 joqmB333z0l/wz3ITfXGuXd7eSqrI2NzHFVJfg7+WrM9AN+5wXD5ugLL8EQd1IN/qPIx zGLSA6A2t5dZglBXll24+Nnsku5Aq0elehuw9GJ48WDZNs9m3hZMMLlomywbPhVx2ztT iCww== X-Gm-Message-State: APjAAAV7x+RMCIvG5LJBQosIAp111aOw1nAGDzaD6quxKJpgoKaZtpPa unI8szCTde4Ns7PtreS9cjxTMZLxjthGbRGpPjJEpg== X-Google-Smtp-Source: APXvYqwYyy9KgiTGpHP2sS9vwQOLD2x36brI3t9Lz0JyNkXI/V0ujixKujae+CsejorzhZpCPEozUOLJZdoSe2VF2eU= X-Received: by 2002:adf:806e:: with SMTP id 101mr2760618wrk.300.1575448886808; Wed, 04 Dec 2019 00:41:26 -0800 (PST) MIME-Version: 1.0 References: <591B421C-F7AB-4394-83B5-AD3A86580C64@lca.pw> <20191203133815.05a020fc@gandalf.local.home> In-Reply-To: <20191203133815.05a020fc@gandalf.local.home> From: Alexander Potapenko Date: Wed, 4 Dec 2019 09:41:15 +0100 Message-ID: Subject: Re: [PATCH RFC v3 18/36] kmsan: disable LOCK_DEBUGGING_SUPPORT To: Steven Rostedt Cc: Qian Cai , 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 , 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 7:38 PM Steven Rostedt wrote: > > On Tue, 3 Dec 2019 16:14:17 +0100 > Alexander Potapenko wrote: > > > On Tue, Dec 3, 2019 at 4:00 PM Qian Cai wrote: > > > > > > > > > > > > > On Dec 3, 2019, at 9:35 AM, Alexander Potapenko = wrote: > > > > > > > > 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 k= ernel 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. > > Note, I'm much more interested in someone running with lockdep than > with KMSAN. Thus, you may not get as much use if you do not work with > lockdep. I enable lockdep first when testing out my code. If KMSAN is > not compatible, it wont get enabled. > > > > > 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. > > > > Function tracing had lots of issues with lockdep, but I worked hard to > make sure they could be compatible. This usually required having the > lockdep code not be traced. Is it possible to have the same with KMSAN. > That is, have KMSAN not look at anything that lockdep does? > > -- Steve Qian, Steve, thanks for the data points. I thought it might be more valuable to cut some edges to make KMSAN available to early users, but in the case most developers use a single build for testing it indeed makes more sense to fix lockdep interoperability. I'll look into that. --=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