port-amd64/38478: panic on boot when attaching cpu17

[Christoph_Egger%gmx.de@localhost]

>Number:         38478
>Category:       port-amd64
>Synopsis:       panic on boot when attaching cpu17
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 21 18:30:00 +0000 2008
>Originator:     Christoph Egger
>Release:        4.99.60
>Organization:
>Environment:
>Description:

The machine has 32 CPUs. It crashes at boot:

[...]
cpu17 at mainbus0 apid 34
panic: cpu at apic id 34 already attached?
Stopped in pid 0.1 (system) at netbsd:breakpoint+0x5:   leave
db{0}> bt
breakpoint() at netbsd:breakpoint+0x5
panic() at netbsd:panic+0x267
cpu_attach() at netbsd:cpu_attach+0x4f7
config_attach_loc() at netbsd:config_attach_loc+0x14d
mpacpi_config_cpu() at netbsd:mpacpi_config_cpu+0x6e
acpi_madt_walk() at netbsd:acpi_madt_walk+0x45
mpacpi_scan_apics() at netbsd:mpacpi_scan_apics+0x111
config_attach_loc() at netbsd:config_attach_loc+0x14d
cpu_configure() at netbsd:cpu_configure+0x26
configure() at netbsd:configure+0x3b
main() at netbsd:main+0x19f
db{0}>

>How-To-Repeat:

Boot NetBSD on a machine with 32 CPUs.

>Fix: