zfs crash on FreeBSD 10.3

[Trond Endrestøl]

On Fri, 14 Oct 2016 00:19-0700, Julian Elischer wrote:

> I attempted to add a second partition to an existing FS pool in FreeBSD 10.3
> and the result was a crash..
> 
> is there anyone out there with a scratch system (10.3) (or two spare drives)
> who can show me this working?
> 
> Does it look familiar to anyone?
> 
> The drive 'boot0' is being used as the root drive, but we are in single user
> mode, so its' read-only at this stage.
> 
> =============== cut-n-paste =============
> 
> [boot -s]
> 
> [...]
> 
> Trying to mount root from zfs:p8/image1 []...
> Enter full pathname of shell or RETURN for /bin/sh:
> PS1="# "
> #
> #
> # ls /dev/gpt
> boot0    boot1

> # zpool attach -f p8 gpt/boot0 gpt/boot1

Do you really need to force zpool to attach the second partition?
What happens if you omit the -f flag?

> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address    = 0x50
> fault code        = supervisor read data, page not present
> instruction pointer    = 0x20:0xffffffff81717063
> stack pointer            = 0x28:0xfffffe0169bfc640
> frame pointer            = 0x28:0xfffffe0169bfc9a0
> 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        = 3 (txg_thread_enter)
> trap number        = 12
> Panic:Thought about setting the watchdog to 10 Minutes
> panic: page fault
> cpuid = 1
> 
> KDB: stack backtrace:
>  stack1 db_trace_self_wrapper+0x2a
>  kdb_backtrace+0x37 vpanic+0xf7
>  panic+0x67 trap_fatal+0x264
>  trap_pfault+0x1c2
>  trap+0x38c
>  calltrap+0x8
>  dsl_scan_sync+0x2f3
>  spa_sync+0x328
>  txg_sync_thread+0x140
>  fork_exit+0x135
>  fork_trampoline+0xe
> 
> KDB: enter: panic
> [ thread pid 3 tid 100328 ]
> Stopped at      kdb_enter+0x50: movq    $0,0x6bd5cd(%rip)
> db> reboot
> 
> I will add that after this, every boot hits this problem. (same stack trace).
> the box is effectively bricked
> (or would be if it weren't just a bhyve image)

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