Re: [PATCH v10 2/5] sched: CGroup tagging interface for core scheduling

[Peter Zijlstra]

On Fri, Jan 22, 2021 at 08:17:01PM -0500, Joel Fernandes (Google) wrote:

> +#ifdef CONFIG_SCHED_DEBUG
> +     /* Read the group cookie. */
> +     {
> +             .name = "core_group_cookie",
> +             .flags = CFTYPE_NOT_ON_ROOT,
> +             .read_u64 = cpu_core_group_cookie_read_u64,
> +     },
> +#endif

> +#ifdef CONFIG_SCHED_DEBUG
> +     /* Read the group cookie. */
> +     {
> +             .name = "core_group_cookie",
> +             .flags = CFTYPE_NOT_ON_ROOT,
> +             .read_u64 = cpu_core_group_cookie_read_u64,
> +     },
> +#endif

AFAICT this leaks kernel pointers. IIRC that was a bad thing.