Re: current kernels hang on i386 and amd64

[Kurt Schreiner <ks%ub.uni-mainz.de@localhost>]

On Fri, May 23, 2008 at 12:52:03AM +0200, Michael Lorenz wrote:
> [...]
> On May 22, 2008, at 18:15, Kurt Schreiner wrote:
> 
> > On Thu, May 22, 2008 at 10:25:23PM +0200, Michael Lorenz wrote:
> >> [...]
> >> On May 22, 2008, at 15:52, Kurt Schreiner wrote:
> >>
> >>> kernels compiled from -current source cvs updated May 22 20:18 MEST
> >>> hang under heavy load.
> >> [...]
> >> Sounds like the same scheduler deadlock I'm seeing on macppc - please
> >> try a kernel with options LOCKDEBUG, if it panics with 'locking
> >> against myself' on a spinlock in sched_nextlwp() it's the same
> >> problem.
> >> There's a PR about it - kern/38707
> > Hm, a LOCKDEBUG kernel panics with (amd64 on Q6600):
> >
> > Mutex error: lockdebug_wantlock 'locking against myself'
> > lock address : 0xffff800053f46d80 type: spin
> > [...]
> > panic: LOCKDEBUG
> >
> > and thats it, no reaction anymore.
> >
> > Looks very similar on i386, but drops to dbb. bt shows sched_nextlwp()
> > somewhere... Couldn't get a dump as "reboot" hangs in syncing disks...
> 
> That looks exactly like what I'm getting.

I applied the patch ad@ attached to kern/38707 and both machines are
running fine now....

Kurt