Re: [RFC][PATCHv6 00/12] printk: introduce printing kernel thread

Steven Rostedt
2017-12-14T17:55:12Z

On Thu, 14 Dec 2017 07:25:51 -0800
Tejun Heo <tj@kernel.org> wrote:

> > 3. Soft-lockups are still theoretically possible with Steven's
> > approach.
> >
> > But it seems to be quite efficient in many real life scenarios,
> > including Tetsuo's stress testing. Or am I wrong?
>
> AFAICS, Steven's approach doesn't fix the livelock that we see quite
> often in the fleet where we don't have a safe context to keep flushing
> messages. This isn't theoretical at all. You simply don't have a
> safe context on the cpu to go to. I said I'd come back with a repro
> case but haven't had a chance to yet. I'll try to do it before the
> end of the year, but idk this is pretty obvious.

Yes! Please create a reproducer, because I still don't believe there is
one. And it's all hand waving until there's an actual report that we can
lock up the system with my approach.

-- Steve