linux-kernel - Re: [PATCH V2] mips: kernel: fix detect_memory

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Date: Tue, 25 Jun 2024 09:52:04 +0200
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Shiji Yang <yangshiji66@...look.com>
Cc: linux-mips@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Javier Martinez Canillas <javierm@...hat.com>,
	Khalid Aziz <khalid@...ehiking.org>, Baoquan He <bhe@...hat.com>,
	Jiaxun Yang <jiaxun.yang@...goat.com>,
	Serge Semin <fancer.lancer@...il.com>, linux-kernel@...r.kernel.org,
	Mieczyslaw Nalewaj <namiltd@...oo.com>
Subject: Re: [PATCH V2] mips: kernel: fix detect_memory_region() function

On Tue, Jun 25, 2024 at 09:44:44AM +0800, Shiji Yang wrote:
> The detect_memory_region() has been broken on 6.6 kernel[1]. This
> patch fixes it by:
> 1. Do not use memcmp() on unallocated memory, as the new introduced
>    fortify dynamic object size check[2] will return unexpected result.

hmm, so there should a new way for doing memory probing without
triggering this fortify check. How do other platforms deal with this ?

> 2. Use a fixed pattern instead of a random function pointer as the
>    magic value.

why is this better ?

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]