linux-kernel - Re: [RFC 0/1] Add sysctl entry for controlling crash_kexec_post

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

Message-ID: <f2fe220f-70c9-7b95-a9cb-4709752e4bdc@igalia.com>
Date:   Sat, 2 Apr 2022 11:01:51 -0300
From:   "Guilherme G. Piccoli" <gpiccoli@...lia.com>
To:     Alejandro Jimenez <alejandro.j.jimenez@...cle.com>, corbet@....net,
        mcgrof@...nel.org, keescook@...omium.org, yzaikin@...gle.com,
        linux-fsdevel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     akpm@...ux-foundation.org, linux@...musvillemoes.dk,
        ebiggers@...gle.com, peterz@...radead.org, ying.huang@...el.com,
        mchehab+huawei@...nel.org, Jason@...c4.com, daniel@...earbox.net,
        robh@...nel.org, wangqing@...o.com, prestwoj@...il.com,
        dsahern@...nel.org, stephen.s.brennan@...cle.com
Subject: Re: [RFC 0/1] Add sysctl entry for controlling
 crash_kexec_post_notifiers

On 01/04/2022 17:22, Alejandro Jimenez wrote:
> I noticed that in contrast to other kernel core parameters (e.g. kernel.panic,
> kernel.panic_on_warn, kernel.panic_print) crash_kexec_post_notifiers is not
> available as a sysctl tunable. I am aware that because it is a kernel core
> parameter, there is already an entry under:
> 
>   /sys/module/kernel/parameters/crash_kexec_post_notifiers
> 
> and that allows us to read/modify it at runtime. However, I thought it should
> also be available via sysctl, since users that want to read/set this value at
> runtime might look there first.
> 
> I believe there is an ongoing effort to clean up kernel/sysctl.c, but it wasn't
> clear to me if this entry (and perhaps the other panic related entries too)
> should be placed on kernel/panic.c. I wanted to verify first that this change
> would be welcomed before doing additional refactoring work.
> 
> I'd appreciate any comments or suggestions.
> 
> Thank you,
> Alejandro

Hi Alejandro, thanks for you patch. I have a "selfish" concern though,
I'll expose it here.

I'm working a panic refactor, in order to split the panic notifiers in
more lists - good summary of this discussion at [0].
I'm in the half of the patches, hopefully next 2 weeks I have something
ready to submit (I'll be out next week).

As part of this effort, I plan to have a more fine-grained control of
this parameter, and it's going to be a sysctl, but not
"crash_kexec_post_notifiers" - this one should be kept I guess due to
retro-compatibility, but it'd be a layer on top oh the new one.
With that said, unless you have urgent needs for this patch to be
reviewed/merged , I'd like to ask you to wait the series and I can loop
you there, so you may review/comment and see if it fits your use case.

Thanks,


Guilherme


[0] https://lore.kernel.org/lkml/YfPxvzSzDLjO5ldp@alley/