[Cake] lockup with multiple cake instances on 3.16.7

[Pete Heist]

> On Feb 1, 2019, at 12:18 AM, Toke Høiland-Jørgensen <toke at redhat.com> wrote:
> 
> (crossed streams; but yeah, basically the same conclusion)

Ok, crossed-crossed streams references it is… :)

>> Do you think this is a correct patch?
> 
> Well, the "correct patch" would be to get upstream fixed :)
> 
> But yeah, I don't think it would hurt to carry this as a workaround
> patch until that happens...
> 
> I guess you could try running it for a while and see if anything else
> blows up? You seem to have quite a knack for getting it to fail... ;)

That sounds reasonable, let me see if I can break it in some different cases.

My guess is, past qdiscs didn’t manage to fill the tailroom space and cause this problem, but I’m not sure…