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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A27D0C433FE for ; Mon, 24 Jan 2022 13:31:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243108AbiAXNbX (ORCPT ); Mon, 24 Jan 2022 08:31:23 -0500 Received: from mail-wr1-f51.google.com ([209.85.221.51]:37696 "EHLO mail-wr1-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239932AbiAXNbX (ORCPT ); Mon, 24 Jan 2022 08:31:23 -0500 Received: by mail-wr1-f51.google.com with SMTP id w11so1460969wra.4; Mon, 24 Jan 2022 05:31:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=l1L2Rdz570mj3uqEMkrYEWll3QovuaRRvHlpZ4r9ZnA=; b=bhb72u64kN2DaaiDRKBm3srYQbPkbni6QUQsNrC6jrwypyAiZXJSO//IsgYjMs7BZF 36NU9jthShdIvrjvG1OpNoIJCYrDUJq+YIPXxQt8pJij3jD3OQgQ6f6x1PhMFpy00pEU dXzoUUETdDYIiHDfd4xUsmUgVnK5mPphq2yh070bsjlEYHpq9qoC7Bi15wZcPSBkHqbi /cf5EwQ3Bk+P26w1SwuXu/naXwdEbUL+eHvj59NvYKboFBmHxc8ZHsKOOspAuAQFdyB1 J+duMHJVyuLBny6yCYMrtYERcAgan+DqjK9bH309hA6xMMw9UN4AZt6aN5ejMILLbgtH pxBQ== X-Gm-Message-State: AOAM530RswOWfhGGm8ovIseSEm6eLokz/M9f2bNNdMwGPaMnblA85Okh cmLZVYLklQ1w2u0UoTjFr84= X-Google-Smtp-Source: ABdhPJwkDMc9NJe+pdTdSaDdZePRKMNgaZ3acGP1cCDaMSrKMK6SWMU13FrrulxNnCj36uSV8RHdvg== X-Received: by 2002:a5d:4bd0:: with SMTP id l16mr14356855wrt.93.1643031081599; Mon, 24 Jan 2022 05:31:21 -0800 (PST) Received: from liuwe-devbox-debian-v2 ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id o3sm14101129wrq.70.2022.01.24.05.31.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jan 2022 05:31:21 -0800 (PST) Date: Mon, 24 Jan 2022 13:31:19 +0000 From: Wei Liu To: Helge Deller Cc: Wei Liu , "Michael Kelley (LINUX)" , Haiyang Zhang , KY Srinivasan , Stephen Hemminger , Wei Hu , Dexuan Cui , "drawat.floss@gmail.com" , hhei , "linux-kernel@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "linux-fbdev@vger.kernel.org" , "dri-devel@lists.freedesktop.org" Subject: Re: [PATCH 1/1] video: hyperv_fb: Fix validation of screen resolution Message-ID: <20220124133119.3yxfr7ypmmdotm6h@liuwe-devbox-debian-v2> References: <1642360711-2335-1-git-send-email-mikelley@microsoft.com> <20220123215606.fzycryooluavtar4@liuwe-devbox-debian-v2> <20220123223030.ijdzrunduww76jiq@liuwe-devbox-debian-v2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Mon, Jan 24, 2022 at 10:52:22AM +0100, Helge Deller wrote: > On 1/23/22 23:30, Wei Liu wrote: > > On Sun, Jan 23, 2022 at 10:27:56PM +0000, Michael Kelley (LINUX) wrote: > >> From: Wei Liu Sent: Sunday, January 23, 2022 1:56 PM > >>> > >>> On Sun, Jan 16, 2022 at 09:53:06PM +0000, Haiyang Zhang wrote: > >>>> > >>>> > >>>>> -----Original Message----- > >>>>> From: Michael Kelley (LINUX) > >>>>> Sent: Sunday, January 16, 2022 2:19 PM > >>>>> To: KY Srinivasan ; Haiyang Zhang > >>> ; Stephen > >>>>> Hemminger ; wei.liu@kernel.org; Wei Hu > >>> ; Dexuan > >>>>> Cui ; drawat.floss@gmail.com; hhei ; > >>> linux- > >>>>> kernel@vger.kernel.org; linux-hyperv@vger.kernel.org; linux- > >>> fbdev@vger.kernel.org; dri- > >>>>> devel@lists.freedesktop.org > >>>>> Cc: Michael Kelley (LINUX) > >>>>> Subject: [PATCH 1/1] video: hyperv_fb: Fix validation of screen resolution > >>>>> > >>>>> In the WIN10 version of the Synthetic Video protocol with Hyper-V, > >>>>> Hyper-V reports a list of supported resolutions as part of the protocol > >>>>> negotiation. The driver calculates the maximum width and height from > >>>>> the list of resolutions, and uses those maximums to validate any screen > >>>>> resolution specified in the video= option on the kernel boot line. > >>>>> > >>>>> This method of validation is incorrect. For example, the list of > >>>>> supported resolutions could contain 1600x1200 and 1920x1080, both of > >>>>> which fit in an 8 Mbyte frame buffer. But calculating the max width > >>>>> and height yields 1920 and 1200, and 1920x1200 resolution does not fit > >>>>> in an 8 Mbyte frame buffer. Unfortunately, this resolution is accepted, > >>>>> causing a kernel fault when the driver accesses memory outside the > >>>>> frame buffer. > >>>>> > >>>>> Instead, validate the specified screen resolution by calculating > >>>>> its size, and comparing against the frame buffer size. Delete the > >>>>> code for calculating the max width and height from the list of > >>>>> resolutions, since these max values have no use. Also add the > >>>>> frame buffer size to the info message to aid in understanding why > >>>>> a resolution might be rejected. > >>>>> > >>>>> Fixes: 67e7cdb4829d ("video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V > >>>>> host") > >>>>> Signed-off-by: Michael Kelley > >>> [...] > >>>> > >>>> Reviewed-by: Haiyang Zhang > >>>> > >>> > >>> Applied to hyperv-fixes. Thanks. > >> > >> This fix got pulled into the fbdev/for-next tree by a new maintainer, Helge Deller. > >> See https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/commit/?h=for-next&id=bcc48f8d980b12e66a3d59dfa1041667db971d86 > > > > OK. I will drop it from hyperv-fixes. Thanks for letting me know! > > Linus hasn't pulled my tree yet, and he will probably not before the > next merge window. So, if this is an urgent bugfix for you, I can offer > to drop it from the fbdev tree and that you take it through the hyperv-fixes tree. > In that case you may add an Acked-by: Helge Deller . > Just let me know what you prefer. Hi Helge Yes, I would like to upstream it as soon as possible so that it can propagate to stable trees and be backported by downstream vendors. I will pick it up in hyperv-fixes. Please drop it from your for-next tree. Thanks, Wei. > > Helge