grub-probe hanging on a bootable root pool. noticed it hung during a update-grub called after kernel upgrade.
~$ dpkg -l grub2* | cat
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===========================================================-======================================-============-==========================================================================
ii grub2 2.00-13ubuntu3+zfs3~raring amd64 GRand Unified Bootloader, version 2 (dummy package)
ii grub2-common 2.00-13ubuntu3+zfs3~raring amd64 GRand Unified Bootloader (common files for version 2)
~$ uname -a
Linux io 3.8.0-30-generic #44-Ubuntu SMP Thu Aug 22 20:52:24 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
~$ zpool status syspool
pool: syspool
state: ONLINE
scan: scrub repaired 0 in 0h1m with 0 errors on Tue Feb 11 16:59:42 2014
config:
NAME STATE READ WRITE CKSUM
syspool ONLINE 0 0 0
scsi-SATA_SAMSUNG_SSD_RBXDFF5Z0A839SE839B5864-part1 ONLINE 0 0 0
errors: No known data errors
and here's the grub-probe output
~$ grub-prove -vvv /
grub-probe: info: cannot open `/boot/grub/device.map': No such file or directory.
grub-probe: info: Looking for /dev/sda1.
grub-probe: info: /dev/sda is a parent of /dev/sda1.
grub-probe: info: /dev/sda1 starts from 2048.
grub-probe: info: opening the device hostdisk//dev/sda.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda' in open_device()
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda1' in open_device()
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda2' in open_device()
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda2'
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda2'
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/apple.c:123: bad magic (found 0xeb63; wanted 0x4552
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-probe: info: Partition 0 starts from 2048.
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-probe: info: Looking for /dev/sda1.
grub-probe: info: /dev/sda is a parent of /dev/sda1.
grub-probe: info: /dev/sda1 starts from 2048.
grub-probe: info: opening the device hostdisk//dev/sda.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda' in open_device()
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/apple.c:123: bad magic (found 0xeb63; wanted 0x4552
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-probe: info: Partition 0 starts from 2048.
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-probe: info: Looking for /dev/sda1.
grub-probe: info: /dev/sda is a parent of /dev/sda1.
grub-probe: info: /dev/sda1 starts from 2048.
grub-probe: info: opening the device hostdisk//dev/sda.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda' in open_device()
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/disk/diskfilter.c:135: Scanning for DISKFILTER devices on disk hostdisk//dev/sda
grub-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub-probe: info: scanning hostdisk//dev/sda for LDM.
grub-probe: info: no LDM signature found.
grub-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub-probe: info: no LVM signature found.
grub-core/partmap/apple.c:123: bad magic (found 0x0; wanted 0x4552
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/partmap/msdos.c:181: partition 1: flag 0x0, type 0x82, start 0xce7c000, len 0x2000000
grub-core/partmap/msdos.c:181: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/msdos.c:181: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0
grub-core/partmap/apple.c:123: bad magic (found 0xeb63; wanted 0x4552
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-probe: info: Partition 0 starts from 2048.
grub-core/kern/disk.c:326: Closing `hostdisk//dev/sda'.
grub-probe: info: opening hostdisk//dev/sda,msdos1.
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda,msdos1'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/partmap/msdos.c:181: partition 0: flag 0x80, type 0xbe, start 0x800, len 0xce7b800
grub-core/kern/fs.c:55: Detecting zfs...
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda1' in open_device()
grub-core/fs/zfs/zfs.c:1136: label ok 0
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:953: check 2 passed
grub-core/fs/zfs/zfs.c:964: check 3 passed
grub-core/fs/zfs/zfs.c:971: check 4 passed
grub-core/fs/zfs/zfs.c:981: check 6 passed
grub-core/fs/zfs/zfs.c:989: check 7 passed
grub-core/fs/zfs/zfs.c:1000: check 8 passed
grub-core/fs/zfs/zfs.c:1010: check 9 passed
grub-core/fs/zfs/zfs.c:1032: check 11 passed
grub-core/fs/zfs/zfs.c:1057: check 10 passed
grub-core/fs/zfs/zfs.c:1081: check 12 passed (feature flags)
grub-core/fs/zfs/zfs.c:1785: endian = -1
grub-core/fs/zfs/zfs.c:578: dva=1, 18140c6
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2542: endian = -1, blkid=0
grub-core/fs/zfs/zfs.c:1899: endian = -1
grub-core/fs/zfs/zfs.c:1925: endian = -1
grub-core/fs/zfs/zfs.c:1785: endian = -1
grub-core/fs/zfs/zfs.c:578: dva=6, 18140b8
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2546: alive
grub-core/fs/zfs/zfs.c:2370: looking for 'features_for_read'
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, c8c649
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2380: zap read
grub-core/fs/zfs/zfs.c:2393: fat zap
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=6, 1beaf91
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2152: fzap: length 18
grub-core/fs/zfs/zfs.c:2397: returned 0
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, 23a
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:1985: zap: name = org.illumos:lz4_compress, value = 1, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:1985: zap: name = , value = 0, cd = 0
grub-core/fs/zfs/zfs.c:3109: alive
grub-core/fs/zfs/zfs.c:2926: endian = 1
grub-core/fs/zfs/zfs.c:2542: endian = 1, blkid=0
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=6, 18140b8
grub-core/fs/zfs/zfs.c:2546: alive
grub-core/fs/zfs/zfs.c:2933: alive
grub-core/fs/zfs/zfs.c:2370: looking for 'root_dataset'
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, c8c649
grub-core/fs/zfs/zfs.c:2380: zap read
grub-core/fs/zfs/zfs.c:2393: fat zap
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=6, 1beaf91
grub-core/fs/zfs/zfs.c:2152: fzap: length 13
grub-core/fs/zfs/zfs.c:2397: returned 0
grub-core/fs/zfs/zfs.c:2939: alive
grub-core/fs/zfs/zfs.c:2945: alive
grub-core/fs/zfs/zfs.c:3118: alive
grub-core/fs/zfs/zfs.c:3122: endian = 0
grub-core/fs/zfs/zfs.c:3132: endian = 1
grub-core/fs/zfs/zfs.c:2991: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, ee
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:3208: endian = 1
grub-core/fs/zfs/zfs.c:2991: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, ee
grub-core/fs/zfs/zfs.c:2542: endian = 1, blkid=0
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, e9
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, e7
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, e5
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, e3
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, e1
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1930: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=2, df
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=3, dc
grub-core/fs/zfs/zfs.c:2546: alive
grub-core/fs/zfs/zfs.c:2370: looking for 'ROOT'
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, 0
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2380: zap read
grub-core/fs/zfs/zfs.c:2384: micro zap
grub-core/fs/zfs/zfs.c:2387: returned 0
grub-core/fs/zfs/zfs.c:2542: endian = 1, blkid=0
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=6, 18140b8
grub-core/fs/zfs/zfs.c:2546: alive
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, 89
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda1'
grub-core/fs/zfs/zfs.c:2442: zap iterate
grub-core/fs/zfs/zfs.c:2446: micro zap
grub-core/fs/zfs/zfs.c:1985: zap: name = $MOS, value = 5, cd = 0
grub-core/fs/zfs/zfs.c:3809: failed here
grub-core/fs/zfs/zfs.c:1899: endian = 1
grub-core/fs/zfs/zfs.c:1925: endian = 1
grub-core/fs/zfs/zfs.c:1785: endian = 1
grub-core/fs/zfs/zfs.c:578: dva=1, 2b
grub-core/kern/disk.c:230: Opening `hostdisk//dev/sda'...
grub-probe: info: the size of hostdisk//dev/sda is 250069680.
grub-core/kern/emu/hostdisk.c:909: opening the device `/dev/sda' in open_device()
grub-core/fs/zfs/zfs.c:1136: label ok 0
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/fs/zfs/zfs.c:953: check 2 passed
grub-core/fs/zfs/zfs.c:3237: incorrect nvlist header
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/fs/zfs/zfs.c:1136: label ok 1
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/fs/zfs/zfs.c:953: check 2 passed
grub-core/fs/zfs/zfs.c:3237: incorrect nvlist header
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/fs/zfs/zfs.c:1136: label ok 2
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/kern/emu/hostdisk.c:886: reusing open device `/dev/sda'
grub-core/fs/zfs/zfs.c:953: check 2 passed
grub-probe hanging on a bootable root pool. noticed it hung during a update-grub called after kernel upgrade.
and here's the grub-probe output