I had this problem and it was indeed related to VMware fusion running and an active virtual machine. It was a bit frustrating in my case as I had a lot of unsaved work open. I couldn't even get the machine to respond by plugging in a USB keyboard / mouse, but I was able to recover using this method.
a) SSH to one's macbook (this however needs the "remote login" sharing feature enabled in the settings).
b) find all the process IDs related to VMware e.g. ps ax | grep -i vmware
c) sudo kill -9 <pid> all the VMware processes (this will simply kill off the running VM, if there is unsaved data in that, you would need to connect over the network to that machine if possible).
d) now connect the USB keyboard, (this should now work, but the inbuilt keyboard still doesn't).
I managed to save my work that way, and reboot. Now I ensure that my VMs are suspended and VMware Fusion is closed, until such time as they figure a fix for this one.
Hope that helps anyone in my situation that doesn't want to power cycle the machine and potentially loose unsaved data....
Chris