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Tue, 14 Oct 2025 17:11:13 -0700 (PDT) Received: by archie.me (Postfix, from userid 1000) id 657784235ADC; Wed, 15 Oct 2025 07:11:10 +0700 (WIB) Date: Wed, 15 Oct 2025 07:11:09 +0700 From: Bagas Sanjaya To: Randy Dunlap , Jonathan Corbet , Linux Kernel Mailing List , Linux Documentation , Linux Serial Cc: Cengiz Can , Tomas Mudrunka , Jiri Slaby , Greg Kroah-Hartman , Anselm =?utf-8?Q?Sch=C3=BCler?= Subject: Re: [PATCH] Documentation: sysrq: Remove contradicting sentence on extra /proc/sysrq-trigger characters Message-ID: References: <20251008112409.33622-1-bagasdotme@gmail.com> <87wm4xbkim.fsf@trenco.lwn.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="LIbl/zC8wYYsbIAH" Content-Disposition: inline In-Reply-To: --LIbl/zC8wYYsbIAH Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 14, 2025 at 10:57:45AM -0700, Randy Dunlap wrote: >=20 >=20 > On 10/14/25 7:55 AM, Jonathan Corbet wrote: > > Bagas Sanjaya writes: > >=20 > >> /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-f77ce0a9d30= 7@anselmschueler.com/ > >> Signed-off-by: Bagas Sanjaya > >> --- > >> 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.:: > >=20 > > 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? >=20 > but the following paragraph says: >=20 > Alternatively, write multiple characters prepended by underscore. > This way, all characters will be processed. E.g.:: >=20 > echo _reisub > /proc/sysrq-trigger >=20 > so it is confuzing. I guess the whole "On all" description can be rewritten like: Write a single character to /proc/sysrq-trigger, e.g.:: ... If a string (multiple characters) is written instead, only the first charac= ter is processed unless the string is prepended by an underscore, like:: ... Thanks. --=20 An old man doll... just what I always wanted! - Clara --LIbl/zC8wYYsbIAH Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQSSYQ6Cy7oyFNCHrUH2uYlJVVFOowUCaO7mmQAKCRD2uYlJVVFO o6ZYAQCwhB3aB0i96VC/SB/7tmP2XGyPcKpB3u3fe4lIlhflcwEA8e0cuJK+EduV PcWc2iPDLvugWW7GlPMI0DUffFJ8bwE= =saSJ -----END PGP SIGNATURE----- --LIbl/zC8wYYsbIAH--