linux-kernel - Re: [PATCH 1/1] Add a new sysctl to disable io

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Message-ID: <CANiDSCtu1OvoRe0ReqBVctzd8euZDt-h7dyx+xACWzdQeHkxBA@mail.gmail.com>
Date:   Wed, 28 Jun 2023 17:59:59 +0200
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Matteo Rizzo <matteorizzo@...gle.com>
Cc:     Bart Van Assche <bvanassche@....org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, io-uring@...r.kernel.org,
        jordyzomer@...gle.com, evn@...gle.com, poprdi@...gle.com,
        corbet@....net, axboe@...nel.dk, asml.silence@...il.com,
        akpm@...ux-foundation.org, keescook@...omium.org,
        rostedt@...dmis.org, dave.hansen@...ux.intel.com,
        chenhuacai@...nel.org, steve@....org, gpiccoli@...lia.com,
        ldufour@...ux.ibm.com
Subject: Re: [PATCH 1/1] Add a new sysctl to disable io_uring system-wide

HI Matteo

On Wed, 28 Jun 2023 at 17:12, Matteo Rizzo <matteorizzo@...gle.com> wrote:
>
> On Wed, 28 Jun 2023 at 13:44, Ricardo Ribalda <ribalda@...omium.org> wrote:
> >
> > Have you considered that the new sysctl is "sticky like kexec_load_disabled.
> > When the user disables it there is no way to turn it back on until the
> > system is rebooted.
>
> Are you suggesting making this sysctl sticky? Are there any examples of how to
> implement a sticky sysctl that can take more than 2 values in case we want to
> add an intermediate level that still allows privileged processes to use
> io_uring? Also, what would be the use case? Preventing privileged processes
> from re-enabling io_uring?

Yes, if this sysctl is accepted, I think it would make sense to make it sticky.

For more than one value take a look to  kexec_load_limit_reboot and
kexec_load_limit_panic

Thanks!

>
> Thanks!
> --
> Matteo



-- 
Ricardo Ribalda