Re: [PATCH net 1/2] net: preserve rps_default_mask on failed writes

[Wang Zhan]

On Wed, 28 Oct 2026 14:52:09 +0000 Yingjie Wang wrote:
> @@ -105,27 +105,29 @@ static int rps_default_mask_sysctl(const struct ctl_table *table, int write,
>  				   void *buffer, size_t *lenp, loff_t *ppos)
>  {
>  	struct net *net = (struct net *)table->data;
> +	struct cpumask *new_mask = NULL;
>  	struct cpumask *mask;
>  	int err = 0;
> 
> +	if (write) {
> +		new_mask = kzalloc(cpumask_size(), GFP_KERNEL);
> +		if (!new_mask)
> +			return -ENOMEM;
> +	}
> +
>  	mutex_lock(&rps_default_mask_mutex);
>  	mask = net->core.rps_default_mask;
>  	if (write) {
> -		if (!mask) {
> -			mask = kzalloc(cpumask_size(), GFP_KERNEL);
> -			net->core.rps_default_mask = mask;
> -		}
> -		err = -ENOMEM;
> -		if (!mask)
> -			goto done;
> -
> -		err = cpumask_parse(buffer, mask);
> +		err = cpumask_parse(buffer, new_mask);
>  		if (err)
>  			goto done;
> 
> -		err = rps_cpumask_housekeeping(mask);
> +		err = rps_cpumask_housekeeping(new_mask);
> +		if (err)
> +			goto done;

Please consider parsing and validating new_mask before taking
rps_default_mask_mutex. It remains private to this handler until published.