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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3CD90C433F5 for ; Mon, 30 May 2022 09:34:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=l8G/fcR5VQoISQ3dVVG3jfrdiwV6rz7XJk+vICuzzjI=; b=4BW9zV+WKmFL5S ByfLl5uU8rRI8qeu/jy3U/0uuBKwT8l6xWRFWu7F8n07VWzzl5OQ9nT0rz41aRLMisjWCipyxlynO 7W9/kcOYSPQUmms7xg9QaAn/oGm4T/uKS2jHZ0iiE6JkIddTYtx+gV+BmLmZ29NE/b442CnzBE9U4 BF+zftVdCC2f2vOxuz8zVAG1zSegOdXyUqauxnzJPt0Vz42fIf2RYzS8tTuaY/PPM/GQQ/zX6js4F SbMpyxYKKNqxayUpH56i1/DT+D4O/rixRu86M02u+7DBxs+ENXWHXhmESWztoriVWL6SsfmjJfgyJ PiPQY7Dx8lRv+6jybXvA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nvbmE-006842-PV; Mon, 30 May 2022 09:33:30 +0000 Received: from mga17.intel.com ([192.55.52.151]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nvbmA-00683S-VY for linux-arm-kernel@lists.infradead.org; Mon, 30 May 2022 09:33:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1653903206; x=1685439206; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=TBSc0KNGpzSlLLY6lieGvmYQxKAskO2xitesyVYh6/0=; b=ey8caMeDwYoSoZtw4NejGYvh84IqetFz8weWxvVDsGM7VoEuRgjLqo/V VPFMJM0WIOdl0XjxHHBaFMm0sesCvqfvGjcpr37QATsWUSKjp9P+yhZeg BTKToGmrP9DUVYKo2k1WAShYS5ZKMh6sZYaiBDevSjKbswyQ+bhts9+J5 YgeHWID6aNRJojmzJyKDgSBFTkLuqinErlGxByvyK9yV3ioAhIS2W4y4+ 7QHAqLQ/3A+YzKTfi7nDPBWXMMg55yCQZKZg6U4IALVnB4Qv9/fF1ejei 4sn25HxKoamYwEaorVd8cZAJU/WivtiMAKtBHCUDO9JikOA/9SILTMyXU A==; X-IronPort-AV: E=McAfee;i="6400,9594,10362"; a="255438534" X-IronPort-AV: E=Sophos;i="5.91,262,1647327600"; d="scan'208";a="255438534" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2022 02:33:26 -0700 X-IronPort-AV: E=Sophos;i="5.91,262,1647327600"; d="scan'208";a="529103807" Received: from jkuna-mobl.ger.corp.intel.com (HELO localhost) ([10.249.150.228]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2022 02:33:20 -0700 From: Jani Nikula To: Linus Torvalds , Arnd Bergmann Cc: Sudip Mukherjee , Russell King , Viresh Kumar , Shiraz Hashim , Ville =?utf-8?B?U3lyasOkbMOk?= , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , dri-devel , Linux Kernel Mailing List , Linux ARM , SoC Team Subject: Re: mainline build failure due to f1e4c916f97f ("drm/edid: add EDID block count and size helpers") In-Reply-To: <87a6aztli2.fsf@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <87a6aztli2.fsf@intel.com> Date: Mon, 30 May 2022 12:33:17 +0300 Message-ID: <877d63tleq.fsf@intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220530_023327_076213_2EFA98F6 X-CRM114-Status: GOOD ( 17.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 30 May 2022, Jani Nikula wrote: > On Sat, 28 May 2022, Linus Torvalds wrote: >> On Sat, May 28, 2022 at 11:59 AM Arnd Bergmann wrote: >>> >>> It's CONFIG_ARM_AEABI, which is normally set everywhere. Without this >>> option, you the kernel is built for the old 'OABI' that forces all non-packed >>> struct members to be at least 16-bit aligned. >> >> Looks like forced word (32 bit) alignment to me. >> >> I wonder how many other structures that messes up, but I committed the >> EDID fix for now. > > Thanks for the fix, and the thorough commit message! > >> This has presumably been broken for a long time, but maybe the >> affected targets don't typically use EDID and kernel modesetting, and >> only use some fixed display setup instead. >> >> Those structure definitions go back a _loong_ time (from a quick 'git >> blame' I see November 2008). >> >> But despite that, I did not mark my fix 'cc:stable' because I don't >> know if any of those machines affected by this bad arm ABI issue could >> possibly care. >> >> At least my tree hopefully now builds on them, with the BUILD_BUG_ON() >> that uncovered this. > > Indeed the bug is ancient. I just threw in the BUILD_BUG_ON() on a whim > as an extra sanity check when doing pointer arithmetics on struct edid > *. > > If there are affected machines, buffer overflows are the real danger due > to edid->extensions indicating the number of extensions. That is, for EDID. Makes you wonder about all the other packed structs with enum members across the kernel. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel