x86_64 boot hang when CONFIG_NUMA=n

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

On 2.6.26-rc[2345], I am seeing a hang during boot with CONFIG_NUMA=n, but changing
to CONFIG_NUMA=y allows successful boot.

This is on a 4-way AMD64 (HP) server with 8 GB RAM.

Using initcall_debug, the last output on a hang is from arch/x86/pci/k8-bus_64.c:

calling  early_fill_mp_bus_info+0x0/0x7b2
node 0 link 1: io port [1000, 3fff]
node 1 link 2: io port [4000, ffff]
TOM: 0000000080000000 aka 2048M
node 0 link 1: mmio [e8000000, fddfffff]
node 1 link 2: mmio [fde00000, fdffffff]
node 0 link 1: mmio [80000000, 83ffffff]
node 1 link 2: mmio [84000000, 8fffffff]
node 0 link 1: mmio [a0000, bffff]
TOM2: 0000000280000000 aka 10240M
bus: [00,3f] on node 0 link 1
bus: 00 index 0 io port: [0, 3fff]
bus: 00 index 1 mmio: [90000000, fddfffff]
bus: 00 index 2 mmio: [80000000, 83ffffff]
bus: 00 index 3 mmio: [a0000, bffff]
bus: 00 index 4 mmio: [fe000000, ffffffff]
bus: 00 index 5 mmio: [280000000, fcffffffff]
bus: [40,ff] on node 1 link 2
bus: 40 index 0 io port: [4000, ffff]
bus: 40 index 1 mmio: [fde00000, fdffffff]


There should be an index 2 line printed next, like this slightly modifed for debug
version does (with CONFIG_NUMA=y), or maybe the following line(s) just aren't
making it to the (net)console log and some other initcall function is actually
hanging:  (??)

bus: [40,ff] on node 1 link 2
bus: 40 index 0/3 io port: [4000, ffff]
bus: 40 index 1/3 mmio: [fde00000, fdffffff]
bus: 40 index 2/3 mmio: [84000000, 8fffffff]
early_fill_mp_bus_info: done


Has anyone seen something like this?  Any patches to test?

The next initcall functions (on a working boot) are:

calling  arch_kdebugfs_init+0x0/0x8
initcall arch_kdebugfs_init+0x0/0x8 returned 0 after 0 msecs
calling  mtrr_if_init+0x0/0x77
initcall mtrr_if_init+0x0/0x77 returned 0 after 0 msecs
calling  ffh_cstate_init+0x0/0x31
initcall ffh_cstate_init+0x0/0x31 returned -1 after 0 msecs
initcall ffh_cstate_init+0x0/0x31 returned with error code -1
calling  acpi_pci_init+0x0/0x4a
ACPI: bus type pci registered
initcall acpi_pci_init+0x0/0x4a returned 0 after 0 msecs


Thanks,
---
~Randy