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Date:   Wed, 5 May 2021 18:50:13 +0200
From:   Borislav Petkov <bp@suse.de>
To:     Andrew Halaney <ahalaney@redhat.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] init: Print out unknown kernel parameters
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On Wed, May 05, 2021 at 11:37:28AM -0500, Andrew Halaney wrote:
> I actually did use that recommendation essentially, the patch I've sent
> is riding on the work done by unknown_bootoption() which is populated by
> iterating over over the different sections parameters can live in - so
> this is only printing out arguments that didn't match a known kernel
> parameter. Sorry if I didn't make that clear earlier, definitely was
> trying to listen to your advice.

Bah, don't take my "advice" too seriously - I'm just throwing out
guesses. :-)

So ok, unknown_bootoption() handles those and AFAICT, that gets passed
to parse_args() with the __start___param and __stop___param range.

But then there is that do_early_param() thing for early params, which
are different and which are between __setup_start and __setup_end -
i.e., the ones I meant above.

And that function doesn't do the unknown bootoption handling ;-\

More fun.

> I'll have to think about this some more (the "did you mean this
> parameter" part).. that seems like it might be more trouble than it is
> worth, but I admittedly haven't looked into those cheap algorithms you
> mentioned yet. The reason I say it might be more trouble than it is
> worth is because it is easy to say "why didn't my param work", then grep
> for it in dmesg and find it in the "Unknown command line parameters"
> list - that's sort of the workflow I imagined would happen when someone
> mucks with their kernel cli and doesn't get the intended result.

Oh sure - that's what I meant with "cheap". If it can't be done
elegantly and easily, just forget it. dmesg | grep is a lot easier. :-)

Thx.

-- 
Regards/Gruss,
    Boris.

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