On Thu, Feb 4, 2021 at 6:02 AM Peter Zijlstra <pet...@infradead.org> wrote: > > 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.
For that matter, we're also exposing the cookie pointer in /proc/$pid/sched. Currently these are used by the selftests to validate that two tasks are/aren't sharing. If this poses a risk, we can rework to avoid exposing the actual pointers.