Mike, On Fri, Jul 30 2021 at 17:21, Mike Galbraith wrote: > On Fri, 2021-07-30 at 13:07 +0200, Sebastian Andrzej Siewior wrote: >> Dear RT folks! >> >> I'm pleased to announce the v5.14-rc3-rt1 patch set. > > Damn, I was hoping to figure out wth is going on before the 62 patch > version of tglx/rtmutex branch made its way out into the big wide > world, but alas, I was too slow. > > I started meeting GUI hangs as soon as I merged the 62 patch series > into my 5.13-rt based master tree. I took tglx/rtmutex (977db8e523f5) > back to 5.13-rt to make sure it wasn't some booboo I had made in the > rolled forward tree, but the hangs followed the backport, and I just > met them in virgin v5.14-rc3-rt1, so unfortunately it wasn't some local > booboo, there's a bug lurking. Maybe a config sensitive one, as what > I'm seeing on my box seems unlikely to escape into the wild otherwise. > > First symptom is KDE/Plasma's task manager going comatose. Notice soon KDE/Plasma points at the new fangled rtmutex based ww_mutex from Peter. I tried to test the heck out of it... Which graphics driver is in use on that machine? > been helpful anyway, box at a glance looks fine. With lockdep enabled, > a failing kernel gets so buggered it isn't even able to crashdump. Ouch. Thanks, tglx