amd64 server hang

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

Last Monday a GENERIC/amd64-current (Mar 24 16:19 GMT code) crashed
rebooted, but sadly didn't leave me a core file.

Today said nfs server froze. Logging in on as root on a serial console
gave me a shell prompt, then ls froze. Dropping into ddb, all 4 CPUs
(2 real hyperthreaded) where idle, and serveral processes were in tstile.

Thoughts on gaining more clues? (An earlier post from wiz about tmpfs &
tstile had me wondering...)

Cheers,

Patrick