gmirror panic on RELENG_8

[Steve Price]

On Tue, Jan 11, 2011 at 12:23 PM, Pawel Jakub Dawidek <pjd at freebsd.org> wrote:
>
> This is very bad idea to turn live disk into a mirror, but I don't
> expect this is the reason of the panic.

Agreed.  This is a dev machine with a fresh install - only 300M
used of a 300GB drive so the likelihood of something being in
the last sector of da0 is near zero.  Just to be safe though I
usually dd the last sector to file just to make sure.

> Panic message and backtrace is minimum what you need to provide.
> Really, even taking photo of your screen with panic message and
> backtrace might be enough.

I'm unable to get a coredump at the moment but here's what
I typed in from a couple of screenshots I took.

SMP: AP CPU #1 Launched!
SMP: AP CPU #2 Launched!
SMP: AP CPU #3 Launched!
Fatal trap 12 with interrupts disabled

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address    = 0x8
fault code                  = supervisor read, page not present
instruction pointer       = 0x20:0xc0bd0c22
stack pointer              = 0x28:0xc1020c7c
frame pointer              = 0x28:0xc1020c94
code segment            = base 0x0, limit 0xfffff, type 0x1b
                                = DPL 0, pres 1, def32 1, gran 1
processor eflags         = resume, IOPL = 0
current process          = 0 (swapper)
trap number               = 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
#0 0xc08e0ef7 at kdb_backtrace+0x47
#1 0xc08b1fb7 at panic+0x117
#2 0xc0be4c93 at trap_fatal+0x323
#3 0xc0be4f10 at trap_pfault+0x270
#4 0xc0be5455 at trap+0x465
#5 0xc0bcc08c at calltrap+0x6
#6 0xc0bd45dc at lapic_handle_intr+0x4c
#7 0xc0bcc455 at Xapic_isr1+0x35
#8 0xc0bd2180 at ioapic_assign_cpu+0x230
#9 0xc0bd0e6a at intr_shuffle_irqs+0xba
#10 0xc08690bc at mi_startup+0xac
#11 0xc0474885 at begin+0x2c
Uptime: 9s
Cannot dump. Device not defined or unavailable.
Automatic reboot in 15 seconds - press a key on the console to abort

-steve