linux-kernel - Re: [PATCH 1/2] x86/boot: Fix memremap of setup

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Message-ID: <YheLYDdG3w6WGhSM@zn.tnic>
Date:   Thu, 24 Feb 2022 14:42:56 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Ross Philipson <ross.philipson@...cle.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        daniel.kiper@...cle.com, dpsmith@...rtussolutions.com,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        luto@...capital.net, kanth.ghatraju@...cle.com,
        trenchboot-devel@...glegroups.com
Subject: Re: [PATCH 1/2] x86/boot: Fix memremap of setup_indirect structures

On Tue, Feb 22, 2022 at 04:01:32PM -0500, Ross Philipson wrote:
> In the ioremap.c module, the check for NULL is only missing in the
> functions we updated but the lack of a check was already there before
> these changes went in.
> 
> In the setup.c and e820.c modules, the check for NULL is missing in the
> functions we updated but the lack of a check was already there before
> these changes went in in those functions. The lack of early_memremap()
> NULL checks can also be found in other functions in those modules.

I don't know how to understand this statement: are you saying that,
because there are other cases where - for whatever reason - the retval
check is not taking place - you should not do it either?

Because I can see other places where the return value is checked. I
mean, if the return value check doesn't matter, why not make this
function simply void and not bother at all?

> Fixing it in other functions and possibly elsewhere in the arch/x86 code
> seems to be out of scope for this patch set. We could send separate
> patches and hunt down other places this check is missing.

That would be appreciated.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette