SMP deadlocks

I am also experiencing SMP related deadlocks when doing parallel compiles
and make -j#. I am running RELENG_5, cvsuped a few hours ago. The
interesting thing is that i can only reproduce the system freeze when i do
not have any debugging enabled in the kernel. With the GENERIC debugger
stuff in the kernel, it does not freeze. This is a real show stopper for
5.3.