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

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

[Masami Hiramatsu]

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)

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

[Andrew Halaney]

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).

I _think_ the only other one is dyndbg based on some grepping. I'm
debating if it makes sense to do something similar there or to actually
use a callback to do some of the work it needs in stealing from the CLI.

For this case though I don't see how you could do anything other than
what you've done here -- you can't modify the params once we've started
processing, and that's what bootconfig needs to do.

Thanks,
Andrew

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

[Masami Hiramatsu]

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)

> 
> I _think_ the only other one is dyndbg based on some grepping. I'm
> debating if it makes sense to do something similar there or to actually
> use a callback to do some of the work it needs in stealing from the CLI.
> 
> For this case though I don't see how you could do anything other than
> what you've done here -- you can't modify the params once we've started
> processing, and that's what bootconfig needs to do.

Actually, if CONFIG_BOOT_CONFIG=y, "bootconfig" is handled before preparing
cmdline strings, because it will copy (append) additional cmdline args
from the bootconfig to the cmdline.
I can remove the "bootconfig" string too. But I think it is better to keep
it in the cmdline so that users can ensure what he passed to the kernel.

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

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

[Masami Hiramatsu]

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>