Re: [PATCH v2 sched_ext/for-6.12] sched_ext: Allow p->scx.disallow only while loading

[Tejun Heo]

On Thu, Aug 01, 2024 at 01:32:59PM -1000, Tejun Heo wrote:
> From 1232da7eced620537a78f19c8cf3d4a3508e2419 Mon Sep 17 00:00:00 2001
> From: Tejun Heo <tj@xxxxxxxxxx>
> Date: Wed, 31 Jul 2024 09:14:52 -1000
> 
> p->scx.disallow provides a way for the BPF scheduler to reject certain tasks
> from attaching. It's currently allowed for both the load and fork paths;
> however, the latter doesn't actually work as p->sched_class is already set
> by the time scx_ops_init_task() is called during fork.
> 
> This is a convenience feature which is mostly useful from the load path
> anyway. Allow it only from the load path.
> 
> v2: Trigger scx_ops_error() iff @p->policy == SCHED_EXT to make it a bit
>     easier for the BPF scheduler (David).
> 
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Reported-by: "Zhangqiao (2012 lab)" <zhangqiao22@xxxxxxxxxx>
> Link: http://lkml.kernel.org/r/20240711110720.1285-1-zhangqiao22@xxxxxxxxxx
> Fixes: 7bb6f0810ecf ("sched_ext: Allow BPF schedulers to disallow specific tasks from joining SCHED_EXT")
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>

Applied to sched_ext/for-6.12.

Thanks.

-- 
tejun