Re: mmiotracer hangs the system

From: Andy Shevchenko
Date: Fri Aug 19 2016 - 09:02:07 EST


On Fri, Aug 19, 2016 at 1:35 PM, karol herbst <karolherbst@xxxxxxxxx> wrote:
> is there any update on that issue I missed somehow? I really don't
> want to leave the mmiotracer in a state, where it breaks something
> while fixing other issues.

No updates. I'm busy right now with more priority tasks and revert
works for me. Issue is reproducible in my case 100%.

So, I would able to attach dmesg in case it would be helpful.
Otherwise tell me exact instructions how to debug the issue.

Here you are:
http://pastebin.com/raw/VfTZENt7

> But for now, without being able to even reproduce the issue, I can't
> really do much, because the code in the current state looks sane to
> me. Maybe this case includes the mmiotracer cleaning things up and
> arms new region for mmiotracing and that's why it fails? Besides that,
> I have no idea and no way to reproduce this, so I can't help this way.

Maybe. First thing happened is iounmap().

> 2016-08-02 18:13 GMT+02:00 Steven Rostedt <rostedt@xxxxxxxxxxx>:
> > On Tue, 2 Aug 2016 19:08:24 +0300
> > Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote:
> >
> >> I don't think so, since linux-next doesn't work until I revert this commit.
> >>
> >> I can try exactly v4.6 (yep, I tried stable versions, including
> >> v4.4.16 that's why all of them failed to me) if you still would like
> >> me to do so.
> >
> > If linux-next doesn't work, then don't bother.
> >
> > That commit obviously broke something and you'll probably need help
> > from Karol to fix it.

--
With Best Regards,
Andy Shevchenko