The keyboard seemed to be non-responsive, and I ran my program under gdb,
and it just stopped on a select() call (waiting for write to a socket).
I tried to kill gdb with ^C, but it didn't respond to that, nor any other
signals than SIGKILL. After the program exited, I saw this on the screen
(a kernel message, confirmed from dmesg):
wait_queue is bad (eip = 00194b43)
q = 005eecf8
*q = 0059af6c
Nothing else, and the machine seems to work ok again. This keyboard
jamming happens on other machines too, but I don't usually get this
message.