RHEL4 smp hangs at boot

[Mark Ortmeyer <morto apl washington edu>]

Hi,

We have recently purchased a dual Xeon processor machine and are trying 
to install RHEL4 smp onto it.

Unfortunately, the machine hangs during boot when the smp option is
selected.  I was able to get the machine configured using the single
processor kernel, however...  Machine hangs before syslog kicks in so we
have little diagnostic information.  Poking around however, I found this
and am wondering if this calls for a kernel recompile:

WARNING: NR_CPUS limit of 1 reached. Processor ignored.

CPUs are Intel Xeon 3.6 GHz with hyperthreading turned off.
RHEL version installed is RHEL4, x86_64, EM64T.
kernel is: 2.6.9-22.ELsmp
CPU:  Dual Intel Xeon - 3.6GHz - EM64T - 2MB Cache - 800 FSB
RAM:  4GB (4 x 1GB) PC2700/DDR333 Registered ECC - Interleaved


Does anyone have any idea why the machine would hang after selecting the 
smp option?

All current updates have been applied.

Other note, I tried booting smp after disabling ACPI in bios but same 
freeze-up behavior with the smp kernel option...

Thanks for any ideas,
-mark