Re: [PATCH v6 08/22] bootconfig: init: Allow admin to use bootconfig for init command line

From: Arvind Sankar <nivedita@alum.mit.edu>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
	Steven Rostedt <rostedt@goodmis.org>,
	Kees Cook <keescook@chromium.org>, Ingo Molnar <mingo@redhat.com>,
	Frank Rowand <frowand.list@gmail.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Namhyung Kim <namhyung@kernel.org>, Tim Bird <Tim.Bird@sony.com>,
	Jiri Olsa <jolsa@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Rob Herring <robh+dt@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 08/22] bootconfig: init: Allow admin to use bootconfig for init command line
Date: Mon, 3 Aug 2020 11:29:59 -0400	[thread overview]
Message-ID: <20200803152959.GA1168816@rani.riverdale.lan> (raw)
In-Reply-To: <20200804000345.f5727ac28647aa8c092cc109@kernel.org>

On Tue, Aug 04, 2020 at 12:03:45AM +0900, Masami Hiramatsu wrote:
> On Sat, 1 Aug 2020 22:33:18 -0400
> Arvind Sankar <nivedita@alum.mit.edu> wrote:
> > 
> > I came across this as I was poking around some of the command line
> > parsing. AFAICT, initargs_found will never be set to true here, because
> > parse_args handles "--" itself by immediately returning: it doesn't
> > invoke the callback for it. So you'd instead have to check the return of
> > parse_args("bootconfig"...) to detect the initargs_found case.
> 
> Oops, good catch!
> Does this fixes the problem?

Note I found the issue by code inspection, I don't have an actual test
case. But the change looks good to me, with one comment below.

> 
>  	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> -	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
> -		   bootconfig_params);
> +	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
> +			 bootconfig_params);
>  
> -	if (!bootconfig_found)
> +	if (IS_ERR(err) || !bootconfig_found)
>  		return;
>  
> +	/* parse_args() stops at '--' and returns an address */
> +	if (!IS_ERR(err) && err)
> +		initargs_found = true;
> +

I think you can drop the second IS_ERR, since we already checked that.

>  	if (!data) {
>  		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
>  		return;
> -- 
> 2.25.1