[CentOS] Odd kernel panic, repeatable

Tue Jun 3 12:09:22 UTC 2014
mark <m.roth at 5-cent.us>

I had an old server die; we had another, same model, sitting around lightly 
used, so I did what I've done before: swap the RAID card into that, swap the 
drives, even putting them in the same bays as the dead one, and boot.

Nope. 100% of the time, when it hits switching roots, it kernel panics.

Adding rdshell to the kernel line does nothing, I get no grub rdshell. Booting 
from a flash drive into rescue, it finds everything, *perfectly*, and mounts 
it all, including the RAID data drives.

I've rebuilt the initrd, and no joy.

Anyone have an idea?