(beagleboneblack/urtwn) Kernel page fault with the following non-sleepable locks held [ssh on rpi2 comparison]

[Ian Lepore]

On Tue, 2016-06-21 at 15:30 -0700, Mark Millard wrote:
> Ian Lepore ian at freebsd.org  wrote on Tue Jun 21 17:55:28 UTC 2016
> :
> 
> > On Tue, 2016-06-21 at 08:11 -0300, Otacílio wrote:
> > > Em 21/06/2016 07:33, Keith White escreveu:
> > > > In an earlier message Ian said that he thought he knew what the
> > > > problem was... 
> > > 
> > > Here the problem occurs  when using wifi. I do not have tested
> > > wired 
> > > because I don't have a cable here.
> > > 
> > > 
> > > []'s
> > > 
> > > -Otacilio
> > 
> > The wifi alignment fault should be fixed as of r302064.  Sorry it
> > took
> > so long.
> > 
> > -- Ian
> > 
> 
> FYI: I've not had any -r301975 problems with WiFi on my rpi2.
> 
> But I cross build for TARGET_ARCH=armv6 with:
> 
> > XCFLAGS+= -march=armv7-a -mcpu=cortex-a7
> > XCXXFLAGS+= -march=armv7-a -mcpu=cortex-a7
> 
> (And similarly for self-hosted.) It may be that the -march and/or 
> -mcpu matter to the code generation and explain my lack of problems.
> 
> The builds also have INVARIANTS and WITNESS off.
> 
> ===
> Mark Millard
> markmi at dsl-only.net

INVARIANTS being on was one of the things required to trigger the
alignment fault.

-- Ian