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Subject: Re: [PATCH v2] init: Print out unknown kernel parameters
To:     Andrew Halaney <ahalaney@redhat.com>, akpm@linux-foundation.org
Cc:     linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
        Borislav Petkov <bp@suse.de>
References: <20210511211009.42259-1-ahalaney@redhat.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <cbd3c07e-9dae-44b2-761e-653bd8d0e930@infradead.org>
Date:   Wed, 12 May 2021 16:00:21 -0700
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On 5/11/21 2:10 PM, Andrew Halaney wrote:
> It is easy to foobar setting a kernel parameter on the command line
> without realizing it, there's not much output that you can use to
> assess what the kernel did with that parameter by default.
> 
> Make it a little more explicit which parameters on the command line
> _looked_ like a valid parameter for the kernel, but did not match
> anything and ultimately got tossed to init. This is very similar to the
> unknown parameter message received when loading a module.
> 
> This assumes the parameters are processed in a normal fashion, some
> parameters (dyndbg= for example) don't register their
> parameter with the rest of the kernel's parameters, and therefore
> always show up in this list (and are also given to init - like the
> rest of this list).
> 
> Another example is BOOT_IMAGE= is highlighted as an offender, which it
> technically is, but is passed by LILO and GRUB so most systems will see
> that complaint.
> 
> An example output where "foobared" and "unrecognized" are intentionally
> invalid parameters:
> 
>   Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.12-dirty debug log_buf_len=4M foobared unrecognized=foo
>   Unknown command line parameters: foobared BOOT_IMAGE=/boot/vmlinuz-5.12-dirty unrecognized=foo

Hi Andrew,
What order is the list of unknown command line parameters listed in?


> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> Suggested-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
> ---
> 
> It's my first time sending a v2 via email, please let me know if I've
> messed that up in anyway. I decided it wasn't worth the effort to do
> "autocorrect" functionality Borislav was pondering about, feel free to
> disagree on that if you have a strong opinion.
> 
> v2: make output on a single line, make function static and __init,
>     include example output in commit message
> 
>  init/main.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)


Thanks.
-- 
~Randy