2.6.29 boot hang

[Randy Dunlap <randy.dunlap@oracle.com>]

(If this is old news, would someone please tell me the status
of this problem?  or if there is a known CPU issue, tell me.
Thanks.)



On a 4-proc x86_64 (HP BladeCenter, AMD CPUs) system, booting 2.6.29
(or earlier, back to 2.6.28-6921-g873392c) hangs during boot.

git bisect says:
873392ca514f87eae39f53b6944caf85b1a047cb is first bad commit
commit 873392ca514f87eae39f53b6944caf85b1a047cb
Author: Rusty Russell <rusty@rustcorp.com.au>
Date:   Wed Dec 31 23:54:56 2008 +1030

    PCI: work_on_cpu: use in drivers/pci/pci-driver.c
~~~~~~~~~~~~~~~~~~~~~

The last messages are usually like this:

Initializing CPU#1
Calibrating delay using timer specific routine.. 5224.09 BogoMIPS (lpj=10448183)
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 1024K (64 bytes/line)
CPU 1/0x2 -> Node 1
CPU: Physical Processor ID: 1
CPU: Processor Core ID: 0
CPU1: Dual-Core AMD Opteron(tm) Processor 8218 stepping 02
lockdep: fixing up alternatives.
Booting processor 2 APIC 0x1 ip 0x6000
Initializing CPU#2
Calibrating delay using timer specific routine.. 5224.12 BogoMIPS (lpj=10448242)
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 1024K (64 bytes/line)
CPU 2/0x1 -> Node 0
CPU: Physical Processor ID: 0
CPU: Processor Core ID: 1
CPU2: Dual-Core AMD Opteron(tm) Processor 8218 stepping 02
lockdep: fixing up alternatives.
Booting processor 3 APIC 0x3 ip 0x6000
Initializing CPU#3
Calibrating delay using timer specific routine.. 5224.11 BogoMIPS (lpj=10448230)
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)


If I change CONFIG_MICROCODE_AMD=y to CONFIG_MICROCODE_AMD=n & rebuild,
the kernel boots successfully.

There are never any kernel oops/panic/error messages.  I suppose that the
CPU microcode update (if there actually is one) causes some kind of
problem that prevents messages.


Suggestions, fixes, etc.??

Thanks,
-- 
~Randy