Re: [PATCH v2] sched_ext: Reject NMI calls to lock-taking kfuncs

[Tejun Heo]

Hello,

On Wed, Sep 02, 2026 at 10:31:24AM +0800, Wanwu Li wrote:
> -	if (sch)
> -		destroy_dsq(sch, dsq_id);
> +	if (!sch)
> +		return;

unlikely(!sch) like the other kfuncs.

> @@ -9756,6 +9755,9 @@ __bpf_kfunc struct task_struct *bpf_iter_scx_dsq_next(struct bpf_iter_scx_dsq *i
>  	if (!kit->dsq)
>  		return NULL;
>
> +	if (!scx_kf_allowed_ctx(kit->dsq->sched))
> +		return NULL;

new(), next() and destroy() always run in the same context, so reject in
bpf_iter_scx_dsq_new() and drop the checks from next() and destroy(). With
kit->dsq left NULL, both are no-ops.

> +static __always_inline bool __scx_kf_allowed_ctx(struct scx_sched *sch,
> +						 const char *who)

No need to wrap.

Thanks.

-- 
tejun