Re: [PATCH v2] sched/psi: fix race between file release and pressure write

[Tejun Heo <tj@kernel.org>]

Hello,

On Fri, Apr 10, 2026 at 08:39:45PM +0800, Edward Adam Davis wrote:
>  static ssize_t pressure_write(struct kernfs_open_file *of, char *buf,
>  			      size_t nbytes, enum psi_res res)
>  {
> -	struct cgroup_file_ctx *ctx = of->priv;
> +	struct cgroup_file_ctx *ctx;
>  	struct psi_trigger *new;
>  	struct cgroup *cgrp;
>  	struct psi_group *psi;
> +	ssize_t ret = 0;
>  
>  	cgrp = cgroup_kn_lock_live(of->kn, false);
>  	if (!cgrp)
>  		return -ENODEV;
>  
> +	ctx = of->priv;
> +	if (!ctx) {

This test likely isn't necessary but that's pre-existing.

> +		ret = -ENODEV;
> +		goto out_unlock;
> +	}
> +
>  	cgroup_get(cgrp);

We don't need get/put if we don't drop the mutex, right?

Thanks.

-- 
tejun