linux-kernel - Re: [PATCH 4/9] cgroup: Print warning when /proc/cgroups is read on v2-only system

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: <Z8cwZluJooqbO7uZ@slm.duckdns.org>
Date: Tue, 4 Mar 2025 06:55:02 -1000
From: Tejun Heo <tj@...nel.org>
To: Michal Koutný <mkoutny@...e.com>
Cc: cgroups@...r.kernel.org, linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org, Josef Bacik <josef@...icpanda.com>,
	Jens Axboe <axboe@...nel.dk>, Johannes Weiner <hannes@...xchg.org>,
	Waiman Long <longman@...hat.com>
Subject: Re: [PATCH 4/9] cgroup: Print warning when /proc/cgroups is read on
 v2-only system

On Tue, Mar 04, 2025 at 04:37:56PM +0100, Michal Koutný wrote:
> As a followup to commits 6c2920926b10e ("cgroup: replace
> unified-hierarchy.txt with a proper cgroup v2 documentation") and
> ab03125268679 ("cgroup: Show # of subsystem CSSes in cgroup.stat"),
> add a runtime message to users who read status of controllers in
> /proc/cgroups on v2-only system. The detection is based on a)
> no controllers are attached to v1, b) default hierarchy is mounted (the
> latter is for setups that neven mount v2 but read /proc/cgroups upon
> boot when controllers default to v2).

I'm hoping that we could deprecate /proc/cgroups entirely. Maybe we can just
warn whenever the file is accessed?

Thanks.

-- 
tejun