Re: [PATCH v2 sched_ext/for-7.1] sched_ext: Fix build errors and unused label warning in non-cgroup configs

[Andrea Righi <arighi@nvidia.com>]

On Sun, Mar 22, 2026 at 02:39:50PM +0800, Cheng-Yang Chou wrote:
> When building with SCHED_CLASS_EXT=y but CGROUPS=n, clang reports errors
> for undeclared cgroup_put() and cgroup_get() calls, and a warning for the
> unused err_stop_helper label.
> 
> EXT_SUB_SCHED is def_bool y depending only on SCHED_CLASS_EXT, but it
> fundamentally requires cgroups (cgroup_path, cgroup_get, cgroup_put,
> cgroup_id, etc.). Add the missing CGROUPS dependency to EXT_SUB_SCHED in
> init/Kconfig.
> 
> Guard cgroup_put() and cgroup_get() in the common paths with:
>   #if defined(CONFIG_EXT_GROUP_SCHED) || defined(CONFIG_EXT_SUB_SCHED)
> 
> Guard the err_stop_helper label with #ifdef CONFIG_EXT_SUB_SCHED since
> all gotos targeting it are inside that same ifdef block.
> 
> Tested with both CGROUPS enabled and disabled.
> 
> Fixes: ebeca1f930ea ("sched_ext: Introduce cgroup sub-sched support")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202603210903.IrKhPd6k-lkp@intel.com/
> Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>

Looks good to me.

Acked-by: Andrea Righi <arighi@nvidia.com>

Thanks,
-Andrea

> ---
>  init/Kconfig       | 2 +-
>  kernel/sched/ext.c | 6 ++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index 06abd8e272cb..487a93e34be9 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1178,7 +1178,7 @@ endif #CGROUP_SCHED
>  
>  config EXT_SUB_SCHED
>          def_bool y
> -        depends on SCHED_CLASS_EXT
> +        depends on SCHED_CLASS_EXT && CGROUPS
>  
>  config SCHED_MM_CID
>  	def_bool y
> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> index 94548ee9ad85..2e7a1259bd7c 100644
> --- a/kernel/sched/ext.c
> +++ b/kernel/sched/ext.c
> @@ -6494,8 +6494,10 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
>  #endif	/* CONFIG_EXT_SUB_SCHED */
>  	return sch;
>  
> +#ifdef CONFIG_EXT_SUB_SCHED
>  err_stop_helper:
>  	kthread_destroy_worker(sch->helper);
> +#endif
>  err_free_pcpu:
>  	for_each_possible_cpu(cpu) {
>  		if (cpu == bypass_fail_cpu)
> @@ -6514,7 +6516,9 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
>  err_free_sch:
>  	kfree(sch);
>  err_put_cgrp:
> +#if defined(CONFIG_EXT_GROUP_SCHED) || defined(CONFIG_EXT_SUB_SCHED)
>  	cgroup_put(cgrp);
> +#endif
>  	return ERR_PTR(ret);
>  }
>  
> @@ -6603,7 +6607,9 @@ static void scx_root_enable_workfn(struct kthread_work *work)
>  	if (ret)
>  		goto err_unlock;
>  
> +#if defined(CONFIG_EXT_GROUP_SCHED) || defined(CONFIG_EXT_SUB_SCHED)
>  	cgroup_get(cgrp);
> +#endif
>  	sch = scx_alloc_and_add_sched(ops, cgrp, NULL);
>  	if (IS_ERR(sch)) {
>  		ret = PTR_ERR(sch);
> -- 
> 2.48.1
>