Re: evbarm hang

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Apr 19, 2019 at 08:33:00PM +1000, matthew green wrote:
> > So here's our deadlock: cpu 0 holds the kernel lock and wants the pool spin
> > mutex; cpu 1 holds the spin mutex and wants the kenrel lock.
> 
> AFAICT, cpu 1 is at fault here.  this locking order is
> backwards.
> 
> not sure why arm32 pmap operations on the kernel map are
> with the kernel lock instead of another lock.  the arm64
> version of this code doesn't take any lock.

Yes, this looks like it can cause lots of problems.

Indeed, I suspect the kernel_lock here could be replaced with pm_lock as
aarch64 does. I will try this.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--