Re: [PATCH v1] mtd: parsers: ofpart: Fix parsing when size-cells is 0

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Francesco Dolcini <francesco@dolcini.it>
Cc: Marek Vasut <marex@denx.de>, Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	linux-mtd@lists.infradead.org,
	Francesco Dolcini <francesco.dolcini@toradex.com>,
	Shawn Guo <shawnguo@kernel.org>,
	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
Date: Mon, 2 Jan 2023 10:40:04 +0100	[thread overview]
Message-ID: <20230102104004.6abae6da@xps-13> (raw)
In-Reply-To: <Y5ydGhn/qYUalamm@francesco-nb.int.toradex.com>

Hi Francesco,

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.

Thanks,
Miquèl

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