btw., in the future you can debug RT-task lockups easier if you do this:
echo 0 > /proc/irq/1/i8042/threaded
echo 0 > /proc/irq/12/i8042/threaded
echo 0 > /proc/irq/4/serial/threaded
SysRq will work if you do this, and if you have a serial console then
doing Alt-F in minicom on the other box will trigger SysRq too - can be
quite handy when everything else is frozen. The 'P' (showPc) option is
the most useful SysRq functionality to debug lockups.
Ingo