Re: [PATCH v5] cgroup: Add new capability to allow a process to migrate other tasks between cgroups

From: Tejun Heo
Date: Tue Dec 13 2016 - 13:47:13 EST

Hello, Casey.

On Tue, Dec 13, 2016 at 10:32:14AM -0800, Casey Schaufler wrote:
> > The trouble is that CAP_SYS_NICE or _RESOURCE (which was tried in an
> > earlier version of this patch) aren't necessarily appropriate for
> > non-android systems. See Andy's objection here:
> >
> Then we need to see what those as-yet-unimplemented systems
> require and how to address them. I don't think that taking
> the "someone might want it" approach is really appropriate.

I understands that there can be reservations regarding adding a new
CAP but this isn't about someone possibly wanting it in the future.
It's more about overloading existing CAPs leading to permitting
unintended operations. e.g. ppl who've been delegating
CAP_SYS_RESOURCES would automatically end up delegating cgroup
organization without intending so. Using an existing cap would have
been nice but it just doesn't look like we have a good one to