From: Tejun Heo <tj@kernel.org>
To: Shaojie Sun <sunshaojie@kylinos.cn>
Cc: "Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cgroup: replace BUG_ON()s in compare_css_sets() with WARN_ON_ONCE()
Date: Thu, 5 Nov 2026 05:52:29 -1000 [thread overview]
Message-ID: <auymPbeInX5BsUMT@slm.duckdns.org> (raw)
In-Reply-To: <20261105124813.862460-1-sunshaojie@kylinos.cn>
On Thu, Nov 05, 2026 at 08:48:13PM +0800, Shaojie Sun wrote:
> compare_css_sets() walks the cgrp_links lists of two css_sets in
> lockstep. Both lists carry exactly one link per hierarchy root, so a
> length or ordering mismatch just means the two css_sets are not the same
> one, which is what the function already reports with "return false".
> The caller keeps walking the hash chain and allocates a new css_set if
> nothing matches.
>
> None of these checks is a user-reachable error path; they are invariant
> checks on kernel-internal bookkeeping that are expected never to fire,
> and each one has a way out.
>
> No functional change for a consistent state.
Why are we changing this now? These never fired, and if they ever fire,
we're in a very deep doodoo.
Thanks.
--
tejun
prev parent reply other threads:[~2026-11-05 15:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-05 12:48 Shaojie Sun
2026-11-05 15:52 ` Tejun Heo [this message]
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