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

[David Vernet <void@manifault.com>]

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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@kernel.org>
> 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@kernel.org>
> Reported-by: "Zhangqiao (2012 lab)" <zhangqiao22@huawei.com>
> Link: http://lkml.kernel.org/r/20240711110720.1285-1-zhangqiao22@huawei.com
> Fixes: 7bb6f0810ecf ("sched_ext: Allow BPF schedulers to disallow specific tasks from joining SCHED_EXT")
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
> David, how does this look?

Looks great, thanks.

Acked-by: David Vernet <void@manifault.com>

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