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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89F9FC433EF for ; Mon, 4 Oct 2021 16:26:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71E806124D for ; Mon, 4 Oct 2021 16:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236963AbhJDQ2K (ORCPT ); Mon, 4 Oct 2021 12:28:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236959AbhJDQ2K (ORCPT ); Mon, 4 Oct 2021 12:28:10 -0400 Received: from mail-io1-xd2e.google.com (mail-io1-xd2e.google.com [IPv6:2607:f8b0:4864:20::d2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28245C061746 for ; Mon, 4 Oct 2021 09:26:21 -0700 (PDT) Received: by mail-io1-xd2e.google.com with SMTP id d18so20925285iof.13 for ; Mon, 04 Oct 2021 09:26:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=zwhqowoXzJuFipJCtXxoOJgFbLCEZ6oYYj5nkHsrECU=; b=MjEdSbK7Tf/fjpwb7Yk8F5uzjjTjzIGJNCAM0AEiXbPEAqmsbThEErq1rFhLkU0Pta d5vOOgij05XSR2qDWiwkwKR3oszOUa03sJ7u/knuZOTnSnBXzQwUSxHHz65obtXMIARC 64mx8oYDuueywYKk07LC4kFvOT9gQI7XVr05I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zwhqowoXzJuFipJCtXxoOJgFbLCEZ6oYYj5nkHsrECU=; b=e16FqH1z4Oi6dkOoYMaNySLgNKOwrh1zN7G8oLjJ5AiZwfOowgoM1NnB8SAXQgThxl fwPYQkS8JYw9yVk57KkoJPR+7numLMj9QhKMv2wksX2SCsIVJZzOQtIgKDrjusXTvnW3 eAaySz/iWd3avP1mKs19Bkv15/T8RnGHR/gJb4DQFnWIO3qwxFRAuLdktOoc4WRwSFbc WchPxdWHhY/Dtiknmqjdgo0EW+2JoLh0BddsKnjNUJRf7TeyyX85+X8mT43o6ZNE4YwA j3gJoA4MrQjyWD5cB4NxTRy0NLnYTYNQDF9+BiIaT1OjFKlOMyhDIs700ayN/+nNhSXw ozyA== X-Gm-Message-State: AOAM531vyIgUGkJxKZMkdf6hAaJ9GmLjCGJxvAeAzABLHfyBFMhdx330 Gc/kUdDLC0H7ZN0M3G8WOW7pVRCLj+/TQw== X-Google-Smtp-Source: ABdhPJw1qNyhRPAiVbLfbM+cd7De63d84Zm0GEDm/2WymFf3nR2iAZoL+SuI27S4dxLig+K/N5q8Qw== X-Received: by 2002:a05:6638:379c:: with SMTP id w28mr11845362jal.140.1633364779800; Mon, 04 Oct 2021 09:26:19 -0700 (PDT) Received: from mail-io1-f44.google.com (mail-io1-f44.google.com. [209.85.166.44]) by smtp.gmail.com with ESMTPSA id w8sm7891049ilo.83.2021.10.04.09.26.19 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Oct 2021 09:26:19 -0700 (PDT) Received: by mail-io1-f44.google.com with SMTP id p80so20952392iod.10 for ; Mon, 04 Oct 2021 09:26:19 -0700 (PDT) X-Received: by 2002:a6b:6a0c:: with SMTP id x12mr9867780iog.177.1633364778729; Mon, 04 Oct 2021 09:26:18 -0700 (PDT) MIME-Version: 1.0 References: <20210914202202.1702601-1-dianders@chromium.org> <20210914132020.v5.2.I62e76a034ac78c994d40a23cd4ec5aeee56fa77c@changeid> In-Reply-To: From: Doug Anderson Date: Mon, 4 Oct 2021 09:26:06 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v5 02/15] drm/edid: Break out reading block 0 of the EDID To: Geert Uytterhoeven Cc: Thierry Reding , Rob Herring , Sam Ravnborg , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Steev Klimaszewski , DRI Development , linux-arm-msm , David Airlie , Maarten Lankhorst , Thomas Zimmermann , Linus W , Bjorn Andersson , Daniel Vetter , Maxime Ripard , Jani Nikula , Linux Kernel Mailing List , Linux-Renesas Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On Mon, Oct 4, 2021 at 8:42 AM Geert Uytterhoeven wrote: > > > - if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL) > > + edid = (u8 *)drm_do_get_edid_base_block(get_edid_block, data, > > + &connector->edid_corrupt, > > + &connector->null_edid_counter); > > + if (IS_ERR_OR_NULL(edid)) { > > + if (IS_ERR(edid)) > > So edid is an error code, not a valid pointer... > > > + connector_bad_edid(connector, edid, 1); > > ... while connector_bad_edid() expects edid to be a valid pointer, > causing a crash: > > Unable to handle kernel NULL pointer dereference at virtual address Sigh. Thanks for the report and analysis. I guess I don't have any displays reporting invalid EDIDs to test with. Hopefully this will help: https://lore.kernel.org/r/20211004092100.1.Ic90a5ebd44c75db963112be167a03cc96f9fb249@changeid/ -Doug