linux-kernel - Re: [PATCH v2 2/2 sched_ext/for-6.16-fixes] sched_ext, sched/core: Don't call scx_group_set_weight() prematurely from sched_create

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] [day] [month] [year] [list]

Message-ID: <aFGx3RzxQnirpWpn@slm.duckdns.org>
Date: Tue, 17 Jun 2025 08:20:13 -1000
From: Tejun Heo <tj@...nel.org>
To: David Vernet <void@...ifault.com>, Andrea Righi <arighi@...dia.com>,
	Changwoo Min <changwoo@...lia.com>
Cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH v2 2/2 sched_ext/for-6.16-fixes] sched_ext, sched/core:
 Don't call scx_group_set_weight() prematurely from sched_create_group()

On Mon, Jun 16, 2025 at 10:13:25AM -1000, Tejun Heo wrote:
> During task_group creation, sched_create_group() calls
> scx_group_set_weight() with CGROUP_WEIGHT_DFL to initialize the sched_ext
> portion. This is premature and ends up calling ops.cgroup_set_weight() with
> an incorrect @cgrp before ops.cgroup_init() is called.
> 
> sched_create_group() should just initialize SCX related fields in the new
> task_group. Fix it by factoring out scx_tg_init() from sched_init() and
> making sched_create_group() call that function instead of
> scx_group_set_weight().
> 
> v2: Retain CONFIG_EXT_GROUP_SCHED ifdef in sched_init() as removing it leads
>     to build failures on !CONFIG_GROUP_SCHED configs.
> 
> Signed-off-by: Tejun Heo <tj@...nel.org>
> Fixes: 819513666966 ("sched_ext: Add cgroup support")
> Cc: stable@...r.kernel.org # v6.12+

Applied 1-2 to sched_ext/for-6.16-fixes.

Thanks.

-- 
tejun