I have tried mingo's SMP deadlock detection patch, and have not been
able to recreate a hang with his patch installed.
I am happy to try other test/debugging kernels or patches if that
would be helpful to anyone working on tracking these problems.
Robert Brown (rgb@phy.duke.edu) is tracking an SMP bug in ethernet
drivers that may be one source of problems. I'll append a recent
email from him in case it's helpful.
Larry