Re: [PATCH] Documentation: sysrq: Remove contradicting sentence on extra /proc/sysrq-trigger characters

From: Jonathan Corbet

Date: Tue Oct 14 2025 - 10:55:31 EST


Bagas Sanjaya <bagasdotme@xxxxxxxxx> writes:

> /proc/sysrq-trigger documentation states that only first character is
> processed and the rest is ignored, yet it is not recommended to write
> any extra characters to it. The latter statement is contradictive as
> these characters are also ignored as implied by preceding sentence.
>
> Remove it.
>
> Link: https://lore.kernel.org/lkml/7ca05672-dc20-413f-a923-f77ce0a9d307@xxxxxxxxxxxxxxxxxx/
> Signed-off-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
> ---
> Documentation/admin-guide/sysrq.rst | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst
> index 9c7aa817adc72d..63ff415ce85d66 100644
> --- a/Documentation/admin-guide/sysrq.rst
> +++ b/Documentation/admin-guide/sysrq.rst
> @@ -77,9 +77,7 @@ On other
> On all
> Write a single character to /proc/sysrq-trigger.
> Only the first character is processed, the rest of the string is
> - ignored. However, it is not recommended to write any extra characters
> - as the behavior is undefined and might change in the future versions.
> - E.g.::
> + ignored. E.g.::

I'm not sure this is right - there is a warning here that additional
characters may acquire a meaning in the future, so one should not
develop the habit of writing them now. After all these years, I think
the chances of fundamental sysrq changes are pretty small, but I still
don't see why we would take the warning out?

jon