Re: [ANNOUNCE] v5.12-rc3-rt3

From: Mike Galbraith
Date: Sun Mar 21 2021 - 23:12:18 EST


On Sun, 2021-03-21 at 08:46 +0100, Mike Galbraith wrote:
> On Sat, 2021-03-20 at 09:18 +0100, Mike Galbraith wrote:
> > On Fri, 2021-03-19 at 23:33 +0100, Sebastian Andrzej Siewior wrote:
> > > Dear RT folks!
> > >
> > > I'm pleased to announce the v5.12-rc3-rt3 patch set.
> >
> > My little rpi4b is fairly unhappy with 5.12-rt, whereas 5.11-rt works
> > fine on it. The below spew is endless, making boot endless. I turned
> > it into a WARN_ON_ONCE to see if the thing would finish boot, and
> > surprisingly, it seems perfectly fine with that bad idea. Having not
> > the foggiest clue what I'm doing down in arm arch-land, bug is in no
> > immediate danger :)
>
> Actually, it looks like a defenseless little buglet, and this gripe
> simply wants to be disabled for RT.

Or completely removed instead.

It's entirely possible I'm missing something obvious to arm experts,
but I don't _think_ the register read needs protection, leaving me
wondering why arch_faults_on_old_pte() was born with that warning.

-Mike