kern/142728: Panic: Fatal trap 12 in g_io_request

[Henry Wong]

A further netboot on the resliced disk but reusing the slices and 
partitions already
created under 8.0 RELEASE still had a panic.

There is a second type of panic that I'm seeing:  Panic:

Fatal trap 9: general protection fault while in kernel mode
cpuid = 2; apic id = 06
instruction pointer     = 0x20:0xffffffff805276a7
stack pointer           = 0x28:0xffffff81d83164b0
frame pointer           = 0x28:0xffffff81d8316500
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 17706 (httpd)
trap number             = 9
panic: general protection fault
cpuid = 0
Uptime: 25m36s
Physical memory: 16369 MB
Dumping 3268 MB:panic: bufwrite: buffer is not busy???
cpuid = 0
Uptime: 25m37s
Automatic reboot in 15 seconds - press a key on the console to abort


With this panic, it looks like it is attempting to take a dump (unlike 
the trap 12)
but stops with a second panic.  There was still no panic dump found in 
the swap area.

The addresses from nm -n /boot/kernel/kernel that are near the 
instruction pointer are:


ffffffff805273b0 t g_bioq_first
ffffffff805273f0 T g_print_bio
ffffffff805274a0 t g_bioq_lock
ffffffff805274e0 t g_bioq_unlock
ffffffff80527520 T g_unregister_classifier
ffffffff805275a0 T g_register_classifier
ffffffff805275f0 T bio_taskqueue
ffffffff80527670 T g_io_request
ffffffff80527800 T g_io_deliver
ffffffff80527a00 t g_bioq_init
ffffffff80527a30 T g_io_init
ffffffff80527a90 T g_alloc_bio
ffffffff80527ab0 T g_clone_bio
ffffffff80527b40 T g_destroy_bio
ffffffff80527b60 T g_delete_data
ffffffff80527bf0 T g_write_data
ffffffff80527c80 T g_read_data
ffffffff80527d40 T g_io_flush
ffffffff80527dd0 T g_io_getattr
ffffffff80527e80 T g_io_schedule_down
ffffffff805280a0 T g_io_schedule_up

Henry Wong