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 5E249C3DA7A for ; Thu, 5 Jan 2023 12:47:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232845AbjAEMrw (ORCPT ); Thu, 5 Jan 2023 07:47:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232370AbjAEMru (ORCPT ); Thu, 5 Jan 2023 07:47:50 -0500 Received: from smtp-out-08.comm2000.it (smtp-out-08.comm2000.it [212.97.32.78]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1B333B931 for ; Thu, 5 Jan 2023 04:47:46 -0800 (PST) Received: from francesco-nb.int.toradex.com (31-10-206-125.static.upc.ch [31.10.206.125]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: francesco@dolcini.it) by smtp-out-08.comm2000.it (Postfix) with ESMTPSA id AE8D6420F17; Thu, 5 Jan 2023 13:47:44 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailserver.it; s=mailsrv; t=1672922865; bh=7bFpsL453HyKnpFTYVsA8GiulGO4aIzlZZqiWerQDnc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=ZuA/8o3DqN/jJk6jp0Tj51u7u0BUh70D58qzkW2BVlmkvtR4wkqVYMSzT2cSUYHq9 xOcMctjqR7WTSKViEQCThyk7TesCKm8l3F71rR2jBoResqN2OFb/ywca3LRrhauaTI GudqHDLVbFNGIJpvHJmixP4a9wlRlgTg5XDvKp29yKKLDto8DNK4LNa7DRrKN4pG8H vH6u0VaaobJZ5jl3mR+gsjOOkkP7CCj+A9ff6o/S2xiGr+dkBk1fp8INNvVLoGyNgL /xYccta3YGuOb0LCPTEhJ+j01BpAY/kHZrwFCVJ09IKIdg1e0ImJ29qthltsWMQTVY 29g+nq+o5uyxQ== Date: Thu, 5 Jan 2023 13:47:40 +0100 From: Francesco Dolcini To: Miquel Raynal Cc: Francesco Dolcini , Marek Vasut , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org, Francesco Dolcini , Shawn Guo , linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, u-boot@lists.denx.de Subject: Re: [PATCH v1] mtd: parsers: ofpart: Fix parsing when size-cells is 0 Message-ID: References: <6f5f5b32-d7fe-13cc-b52d-83a27bd9f53e@denx.de> <20221216120155.4b78e5cf@xps-13> <20221216143720.3c8923d8@xps-13> <20221216163501.1c2ace21@xps-13> <20230102104004.6abae6da@xps-13> <20230105123334.7f90c289@xps-13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230105123334.7f90c289@xps-13> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hello Miquel, On Thu, Jan 05, 2023 at 12:33:34PM +0100, Miquel Raynal wrote: > miquel.raynal@bootlin.com wrote on Mon, 2 Jan 2023 10:40:04 +0100: > > francesco@dolcini.it wrote on Fri, 16 Dec 2022 17:30:18 +0100: > > > On Fri, Dec 16, 2022 at 04:35:01PM +0100, Miquel Raynal wrote: > > > > marex@denx.de wrote on Fri, 16 Dec 2022 15:32:28 +0100: > > > > > The second part of the message, as far as I understand it, is > > > > > "ignore problems this will cause to users of boards we do not know > > > > > about, let them run into unbootable systems after some linux kernel > > > > > update, > > > > > > > > Now you know what kernel update will break them, so you can prevent it > > > > from happening. > > > > > > > > For boards without even a dtsi in the kernel, should we care? > > > > > > Would caring for those boards not be just exact the same as caring for > > > some UEFI/ACPI mess for which no source code is normally available and > > > nobody really known at which point the various vendors have forked their > > > source code from some Intel or AMD or whatever reference code? > > > > I am sorry I don't know UEFI/ACPI well enough to discuss it. > > > > > IMHO we should care for the multiple reason I have already written in my > > > previous emails. > > > > > > And honestly, just as a side comment, I would feel way more happy > > > to know that the elevator control system in the elevator I use everyday > > > or the chemical industrial plan HMI next to my home is running an up to > > > date Linux system that is not affected by known security vulnerabilities > > > and they did stop updating it just because there was some random bug > > > preventing the updated kernel to boot and nobody had the time/skill to > > > investigate and fix it. [1] > > > > The issue comes from a very specific U-Boot function that should have > > never existed. I hope people working on chemical plants do not make > > use of these and will not disregard the "your DT is broken there [...]" > > warning we plan to add right before their updated board will fail. We > > are not living people in the dark, I agreed for a warning, but I don't > > think applying the proposed fix blindly is wise and future-proof. > > Let's move forward with this. Let's assume my fears are baseless. We > might consider the situation where someone tries to hide the partitions > by setting #size-cell to 0 even wronger and too unlikely. Hopefully we > will not break any other existing setups by applying an always-on fix. Nice, good! > I would still like to see U-Boot partitions handling evolve, at least: > - fix #size-cells in fdt_fixup_mtd() > - avoid the fdt_fixup_mtd() call from Collibri boards (ie. an example > that can be followed by the other users) Fine, I can do it. However I am just not 100% sure about your proposal, I wonder if we should just deprecate this function or we should fix it. The exact end result will depend on the discussion with the U-Boot folks, but I absolutely agree that the current situation needs to change. I'll keep you in CC on those patches. > On Linux side let's fix #size-cells like you proposed without filtering > against a list of compatibles. We however need to improve the > heuristics: > - Do it only when there are partitions declared within a NAND > controller node. > - Change the warning to avoid mentioning backward compatibility, just > mention this is utterly wrong and thus the value will be set to 1 > instead of 0. > - Mention in the comment above this only works on systems with <4GiB > chips. > If you think about other conditions please feel free to add them. > > Do you concur? Yes, I do agree. Side comment, I have been recently busy with other life AND work priorities and this task was just idling on the bottom of my backlog. I do not see the situation improving that much in the next few weeks. Said that patches coming, I am committed to have this sorted out before the next Linux Kernel merge window, for U-Boot the merge window opens in 3 days and I am already late, let's see, this might be as well considered a fix that is fine for a late integration. Francesco