Re: [PATCH 0/3] drm: commit_work scheduling

[Qais Yousef]

On 09/24/20 10:49, Daniel Vetter wrote:

[...]

> > > I also thought kernel threads can be distinguished from others, so
> > > userspace shouldn't be able to sneak in and get elevated by accident.
> > 
> > I guess maybe you could look at the parent?  I still would like to
> > think that we could come up with something a bit less shaking than
> > matching thread names by regexp..
> 
> ps marks up kernel threads with [], so there is a way. But I haven't
> looked at what it is exactly that tells kernel threads apart from others.
> 
> But aside from that sounds like "match right kernel thread with regex and
> set its scheduler class" is how this is currently done, if I'm
> understanding what Tejun and Peter said correctly.
> 
> Not pretty, but also *shrug* ...

Isn't there a real danger that a sneaky application names its threads to match
this regex and get a free promotion to RT without having the capability to do
so?

Cheers

--
Qais Yousef