I'm seeing a hang during boot on my test box running the current tree,
It doesn't always happen, perhaps one in five boots.
I managed to get a partial trace after booting with earlyprintk=vga
Looks like something overflowed the stack.
This is just a quad-core i5, nothing fancy numa-wise.
This code was added in a0acda917284183f9b71e2d08b0aa0aea722b321