Re: [PATCH v5 06/16] printk: Check that index is not defined when a console is preferred via devname

[John Ogness]

On 2026-09-29, Petr Mladek <pmladek@xxxxxxxx> wrote:
> The current code makes sure that a valid index is defined when a console
> is preferred via a name.
>
> On the contrary, the index must not be defined when the console is
> defined via a devname. The index will be defined later when the device
> matches and gets registered.
>
> Enforce the 2nd rule. Make the checks symmetric in the code.
> Do not ignore the errors quietly.
>
> Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>

Reviewed-by: John Ogness <john.ogness@xxxxxxxxxxxxx>

Minor nit below.

> ---
>  kernel/printk/printk.c | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 0199c918ef03..b8c348e305eb 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2559,7 +2559,7 @@ asmlinkage __visible void early_printk(const char *fmt, ...)
>   * it updates some global variables which are used to make the right decisions
>   * in register_console(). Finally, it enforces some rules:
>   *
> - *   1. Either @name OR @devname are allowed. [*]
> + *   1. Either @name and valid @idx OR @devname and @idx=-1 are allowed.
>   *
>   *  [*] A valid @name and @idx will get assigned for a devname later when
>   *	@devname matches during the device initialization, see

You drop the [*] from rule #1. I think this was unintentional,
considering you later add a [**] for rule #4.

John