Re: [PATCH] init: Suppress wrong warning for bootconfig cmdline parameter

[Masami Hiramatsu <mhiramat@kernel.org>]

On Fri, 6 Aug 2021 22:49:41 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hi Andrew,
> 
> On Thu, 5 Aug 2021 10:22:21 -0500
> Andrew Halaney <ahalaney@redhat.com> wrote:
> 
> > On Thu, Aug 05, 2021 at 11:10:51AM +0900, Masami Hiramatsu wrote:
> > > Since the 'bootconfig' command line parameter is handled before
> > > parsing the command line, it doesn't use early_param(). But in
> > > this case, kernel shows a wrong warning message about it.
> > > 
> > > [    0.013714] Kernel command line: ro console=ttyS0  bootconfig console=tty0
> > > [    0.013741] Unknown command line parameters: bootconfig
> > > 
> > > To suppress this message, add a dummy handler for 'bootconfig'.
> > > 
> > > Fixes: 86d1919a4fb0 ("init: print out unknown kernel parameters")
> > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > > ---
> > >  init/main.c |    9 +++++++--
> > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/init/main.c b/init/main.c
> > > index f5b8246e8aa1..8d97aba78c3a 100644
> > > --- a/init/main.c
> > > +++ b/init/main.c
> > > @@ -397,6 +397,12 @@ static int __init bootconfig_params(char *param, char *val,
> > >  	return 0;
> > >  }
> > >  
> > > +static int __init warn_bootconfig(char *str)
> > > +{
> > > +	/* The 'bootconfig' has been handled by bootconfig_params(). */
> > > +	return 0;
> > > +}
> > > +
> > >  static void __init setup_boot_config(void)
> > >  {
> > >  	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
> > > @@ -475,9 +481,8 @@ static int __init warn_bootconfig(char *str)
> > >  	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
> > >  	return 0;
> > >  }
> > > -early_param("bootconfig", warn_bootconfig);
> > > -
> > >  #endif
> > > +early_param("bootconfig", warn_bootconfig);
> > >  
> > >  /* Change NUL term back to "=", to make "param" the whole string. */
> > >  static void __init repair_env_string(char *param, char *val)
> > > 
> > 
> > Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
> > 
> > Thanks Masami, this is one of the corner case command line parameters
> > that I was trying to highlight when I made the original commit (but I
> > didn't catch this one).
> 
> But if there are other parameters which also depends on kconfig?
> This actually depends on CONFIG_BOOT_CONFIG=y. I guess there are
> other parameters which are also depends on kconfig.
> (and usually, developers doesn't change their grub.conf when he install
>  a new kernel)

Ah, sorry. I misunderstood. With your patch, the kernel can notice that 
the kernel may not be correctly configured too.

Thank you!

-- 
Masami Hiramatsu <mhiramat@kernel.org>