linux-kernel - Re: [PATCH 4/4] cgroup: Do not report unavailable v1 controllers in /proc/cgroups

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: <aHGM6_WOTWLiUdpU@slm.duckdns.org>
Date: Fri, 11 Jul 2025 12:15:07 -1000
From: Tejun Heo <tj@...nel.org>
To: Michal Koutný <mkoutny@...e.com>
Cc: Ben Hutchings <ben@...adent.org.uk>, cgroups@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Zefan Li <lizefan.x@...edance.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	Muchun Song <muchun.song@...ux.dev>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Chen Ridong <chenridong@...wei.com>, 1108294@...s.debian.org
Subject: Re: [PATCH 4/4] cgroup: Do not report unavailable v1 controllers in
 /proc/cgroups

On Fri, Jul 11, 2025 at 03:10:44PM +0200, Michal Koutný wrote:
> Hello Ben.
> 
> On Wed, Jul 09, 2025 at 08:22:09PM +0200, Ben Hutchings <ben@...adent.org.uk> wrote:
> > Would you consider reverting this change for the sake of compatibility?
> 
> As you write, it's not fatally broken and it may be "just" an issue of
> container images that got no fresh rebuild. (And I think it should be
> generally discouraged running containers with stale deps in them.)
> 
> The original patch would mainly serve legacy userspace (host) setups on
> top of contemporary kernel (besides API purity reasons). Admittedly,
> these should be rare and eventually extinct in contrast with your
> example where it's a containerized userspace (which typically could do
> no cgroup setup) that may still have some user demand.
> 
> So, I'd be more confident with the revert if such an adjustment was
> carried downstream by some distro and proven its viability first. Do you
> know of any in the wild?

I think we still want to deprecate /proc/cgroups but given that there are
impacted users maybe we can bring it back under a boottime param w/ warning?

Thanks.

-- 
tejun