From: Tejun Heo <tj@kernel.org>
To: Wanwu Li <liwanwu@kylinos.cn>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2] sched_ext: Fix NULL sched deref in kfunc sub-sched error paths
Date: Wed, 2 Sep 2026 09:39:59 -1000 [thread overview]
Message-ID: <aph7j7b_rqqqcSwR@slm.duckdns.org> (raw)
In-Reply-To: <d819e8358fffc09015feffad57794f7c@kernel.org>
On Wed, Sep 02, 2026 at 09:37:39AM -1000, Tejun Heo wrote:
> > + scx_error(scx_task_sched_rcu(p) ?: sch,
> > + "__scx_bpf_select_cpu_and() must be used");
>
> As the fallback only triggers for tasks already past sched_ext_dead() (or
> idle tasks), tearing down the root scheduler doesn't make sense. How about
> adding a flag to the root sched and printing a warning once instead?
It'd be fine to just ignore it too. The scx_error() is there to flag cases
where things went obviously wrong. I don't think we'd lose anything
meaningful by just ignoring it when sch can't be determined.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-09-02 19:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 15:36 [PATCH] sched_ext: Fix NULL sched deref in select_cpu_and sub-sched error path Wanwu Li
2026-09-02 16:14 ` Andrea Righi
2026-09-02 16:34 ` liwanwu
2026-09-02 17:07 ` [PATCH v2] sched_ext: Fix NULL sched deref in kfunc sub-sched error paths Wanwu Li
2026-09-02 18:11 ` Andrea Righi
2026-09-02 19:37 ` Tejun Heo
2026-09-02 19:39 ` Tejun Heo [this message]
2026-09-03 6:06 ` [PATCH v3] " Wanwu Li
2026-09-03 17:56 ` Tejun Heo
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