Re: [PATCH stable 5.10 0/3] ARM FDT relocation backports - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Ard Biesheuvel <ardb@kernel.org>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"# 3.4.x" <stable@vger.kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Russell King <linux@armlinux.org.uk>,
	Nicolas Pitre <nico@fluxnic.net>, Mike Rapoport <rppt@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nick Desaulniers <ndesaulniers@gooogle.com>,
	Joe Perches <joe@perches.com>, Max Filippov <jcmvbkbc@gmail.com>,
	Tian Tao <tiantao6@hisilicon.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
	Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH stable 5.10 0/3] ARM FDT relocation backports
Date: Mon, 10 May 2021 11:46:48 +0200	[thread overview]
Message-ID: <YJkBCMUpKUax0idB@kroah.com> (raw)
In-Reply-To: <CACRpkdb+4OFpsJAPkEjTBBf_+VTUvKkzsDb9xaSOxqhNSWkeeg@mail.gmail.com>

On Mon, May 10, 2021 at 11:37:01AM +0200, Linus Walleij wrote:
> On Mon, May 10, 2021 at 9:43 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Sun, May 09, 2021 at 06:22:05PM -0700, Florian Fainelli wrote:
> 
> > > This does not qualify as a regression in that it has never worked for
> > > the specific platform that I have shown above until your 3 commits came
> > > in and fixed that particular FDT placement. To me this qualifies as a
> > > bug fix, and given that the 3 (now 4) commits applied without hunks, it
> > > seems reasonable to me to back port those to stable.
> >
> > As this isn't a regression, why not just use 5.12 on these platforms?
> > Why is 5.4 and 5.10 needed?
> 
> Actually I think it *is* a regression, but not a common one. The bug that
> Ard is fixing can appear when the kernel grows over a certain size.
> 
> If a user compile in a new set of functionality and the kernel size
> reach a tripping point so that the DTB ends up just outside the 1:1
> lowmem map, disaster strikes.
> 
> This has been a long standing mysterious bug for people using
> attached device trees.

Ok, then feel free to ack them when they get resubmitted.

thanks,

greg k-h