From: Dave Hansen <haveblue@us.ibm.com>

__alloc_bootmem_core() has a couple of BUG_ON()'s.  Since the handlers
aren't set up this early, if you hit it, you just get along stream of
"Unknown Interrupt" messages.  It would be very nice to have a little
bit more information when something has decided to BUG() out this
early.