I've got panic "CPU class not configured" on today's CURRENT.
I have HP Proliant ML370 G4 machine with Xeon CPU 3.20GHz CPU.
When machine tries to boot following message appears:
CPU: Intel(R) Xeon(TM) CPU 3.20GHz (Unknown-class CPU)
logical CPUs per core: 2
panic: CPU class not configured
cpuid = 0
KDB: enter: panic
[thread pid 0 tid 0 ]
stopped at kdb_enter+0x2b : nop