linux-kernel - Re: [PATCH v3] Documentation: sysrq: Rewrite /proc/sysrq-trigger usage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <e86ccc1d-c1b7-409d-a003-2c4e21b1cd62@infradead.org>
Date: Wed, 22 Oct 2025 21:42:46 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Bagas Sanjaya <bagasdotme@...il.com>,
 Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
 Linux Documentation <linux-doc@...r.kernel.org>,
 Linux Serial <linux-serial@...r.kernel.org>
Cc: Jonathan Corbet <corbet@....net>, Cengiz Can <cengiz@...nel.wtf>,
 Tomas Mudrunka <tomas.mudrunka@...il.com>, Jiri Slaby
 <jirislaby@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Anselm Schüler <mail@...elmschueler.com>
Subject: Re: [PATCH v3] Documentation: sysrq: Rewrite /proc/sysrq-trigger
 usage



On 10/22/25 6:41 PM, Bagas Sanjaya wrote:
> /proc/sysrq-trigger usage documentation (in "On all" section) states
> that it is not recommended to write extra characters to it. The sentence
> may imply a contradiction to previous sentence which writes that such
> characters are ignored.
> 
> Rewrite the description.
> 
> Link: https://lore.kernel.org/lkml/7ca05672-dc20-413f-a923-f77ce0a9d307@anselmschueler.com/
> Signed-off-by: Bagas Sanjaya <bagasdotme@...il.com>

Reviewed-by: Randy Dunlap <rdunlap@...radead.org>
Tested-by: Randy Dunlap <rdunlap@...radead.org>

Thanks.

> ---
> Changes since v2 [1]:
> 
>   - Keep /proc/sysrq-trigger future API change note (Tomas)
> 
> Anselm: Do you object to the rewrite?
> 
> [1]: https://lore.kernel.org/linux-doc/20251016103609.33897-2-bagasdotme@gmail.com/
> 
>  Documentation/admin-guide/sysrq.rst | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst
> index 9c7aa817adc72d..a88266b171aa17 100644
> --- a/Documentation/admin-guide/sysrq.rst
> +++ b/Documentation/admin-guide/sysrq.rst
> @@ -75,16 +75,15 @@ On other
>  	submit a patch to be included in this section.
>  
>  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.::
> +	Write a single character to /proc/sysrq-trigger. E.g.::
>  
>  		echo t > /proc/sysrq-trigger
>  
> -	Alternatively, write multiple characters prepended by underscore.
> -	This way, all characters will be processed. E.g.::
> +	Only the first character is processed; any following characters are
> +	ignored for now, which might change in the future.
> +
> +	Alternatively, to write multiple characters, prepend them with an
> +	underscore so that these all will be processed. E.g.::
>  
>  		echo _reisub > /proc/sysrq-trigger
>  
> 
> base-commit: 0aa760051f4eb3d3bcd812125557bd09629a71e8

-- 
~Randy