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=-8.3 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 6B42BC43331 for ; Fri, 27 Mar 2020 18:46:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 318DB206F2 for ; Fri, 27 Mar 2020 18:46:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="QCfPkJYL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 318DB206F2 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 B6B236B0010; Fri, 27 Mar 2020 14:46:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B1B4E6B0032; Fri, 27 Mar 2020 14:46:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0B4C6B0036; Fri, 27 Mar 2020 14:46:23 -0400 (EDT) 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 89E9D6B0010 for ; Fri, 27 Mar 2020 14:46:23 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 30ED88248068 for ; Fri, 27 Mar 2020 18:46:23 +0000 (UTC) X-FDA: 76642022646.17.coil41_71f458dc93d2e X-HE-Tag: coil41_71f458dc93d2e X-Filterd-Recvd-Size: 5626 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Fri, 27 Mar 2020 18:46:22 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id s1so12680310wrv.5 for ; Fri, 27 Mar 2020 11:46:22 -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=U4o33PcHCz6eYFBx+HBTlsdzTSJQGaTP/+nfUW/s+Pk=; b=QCfPkJYLU1Q5tQagQX0hmO+k4U0VbnJbiV0j7wJf3W2KvuINVN1HUD/QSsVnDTDbOZ 5TDPXv8a+x0tb+HnL+0iX1xl7/i83tdvKUk8CyFF8oCCOAQGOpeo1y/P3x6Ip5CXpSt6 T3/UEPxG9lcGboIGx8pHeFGz65CMOsAECx7o6IU2RJkniAabI5P9GMpAoRDeiY+P0nDP vxYaJ+S6fTF7boCxHlR3ICFeGD+AtXzu20CiaVLpUYQ+iR+F+65axCeY/hEck8Dl3yHQ DyDQsFMO5eBX9tFejzp9AP3Ux8I08i26CsSQYjB+DSfBWdykqQtaFXqFNzSVoRwgoZQK WjxQ== 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=U4o33PcHCz6eYFBx+HBTlsdzTSJQGaTP/+nfUW/s+Pk=; b=LES3p431WzqxCjfKGGeMkZ0NABF8cUGj7tsWJqBEpaAwF1cSbKkr+l3toBTmsQBcAU 8/7RxqB6yeHkP8kf0XGOESRLFDN3EsfQPHkFAvCUZ7IU3DJFOZwU+WsxxjEhXdYPAokL wjegpnd22Ah1Cne59nee/i8i82phqJlWphJB0wBPUMlaWvIxlz1taZxD0aMYlyduF05+ v+CaKz1WLvkm9Bxw5avVEZDw4hpxpcdg8EA0WOfcRXHQ/quV0ExddtkeKhM4hT6w40vU GvV8XDgbjYHm3scFnpEJ+nXXcSDBBHhExlEv9R9JI2kT02TfzvqD74/XLNPByYvd4WE1 ixlg== X-Gm-Message-State: ANhLgQ14QCZkZxXgqjQWnixEJ/qy0BKPSnRPDwXSjUT8cPT2c9Wqkmf+ CAqzyBFK8GreIyQoU2v6EP68e5FiuNsS9Bf61JyWsg== X-Google-Smtp-Source: ADFU+vv2Pb0scL7mCvGG6BoxC7N0O7nsck0jNlxkn4sPeiN+K3ZLXWaF2aPrBQ/ZFXQmf3aGZK0HZ7ANDWjWEw8xXfc= X-Received: by 2002:a05:6000:100f:: with SMTP id a15mr816382wrx.382.1585334780057; Fri, 27 Mar 2020 11:46:20 -0700 (PDT) MIME-Version: 1.0 References: <20200325161249.55095-1-glider@google.com> <20200325161249.55095-35-glider@google.com> <20200325161905.GA19868@lst.de> <20200327170647.GA22758@lst.de> In-Reply-To: <20200327170647.GA22758@lst.de> From: Alexander Potapenko Date: Fri, 27 Mar 2020 19:46:08 +0100 Message-ID: Subject: Re: [PATCH v5 34/38] kmsan: dma: unpoison memory mapped by dma_direct_map_page() To: Christoph Hellwig Cc: Marek Szyprowski , Robin Murphy , Vegard Nossum , Dmitry Vyukov , Marco Elver , Andrey Konovalov , Linux Memory Management List , Al Viro , Andreas Dilger , Andrew Morton , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , "Darrick J. Wong" , David Miller , Dmitry Torokhov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Mark Rutland , "Martin K . Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S. Tsirkin" , Michal Hocko , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , 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 Fri, Mar 27, 2020 at 6:06 PM Christoph Hellwig wrote: > > On Fri, Mar 27, 2020 at 06:03:32PM +0100, Alexander Potapenko wrote: > > > Also the page > > > doesn't have to be mapped into kernel address space, you probably > > > want to pass the page to kmsan_handle_dma and throw in a highmem > > > check there. > > > > Do you mean comparing the address to TASK_SIZE, or is there a more > > portable way to check that? > > !PageHighMem(page) implies the page has a kernel direct mapping. I tried adding this check and started seeing false positives because the virtio_ring driver actually uses highmem pages for DMA, and data from those pages is later copied to the kernel. Guess it's easier to just allow handling highmem pages? What problems do you anticipate? --=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