linux-kernel - Re: [PATCH v2 4/4] sched_ext: Fix cgroup exit ordering by moving sched_ext_free() to finish_task

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: <aQkRKC15ta5Wo-lU@slm.duckdns.org>
Date: Mon, 3 Nov 2025 10:31:36 -1000
From: Tejun Heo <tj@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: David Vernet <void@...ifault.com>, Andrea Righi <arighi@...dia.com>,
	Changwoo Min <changwoo@...lia.com>,
	Dan Schatzberg <dschatzberg@...a.com>, linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org, sched-ext@...ts.linux.dev
Subject: Re: [PATCH v2 4/4] sched_ext: Fix cgroup exit ordering by moving
 sched_ext_free() to finish_task_switch()

Hello,

On Mon, Nov 03, 2025 at 09:28:43PM +0100, Peter Zijlstra wrote:
> > @@ -5222,6 +5222,12 @@ static struct rq *finish_task_switch(str
> >  		if (prev->sched_class->task_dead)
> >  			prev->sched_class->task_dead(prev);
> 
> ^^^ can you not use task_dead_scx() ?

Unfortunately not. Because sched class switches are atomic infallible
operations, all tasks in the system must be prepped on scheduler attach &
fork regardless of their current sched class and thus have to be cleaned up
in the same way on detach & exit.

Thanks.

-- 
tejun