[BeagleBone Black] Issue of "Unable to unwind further"

[Xuebing Wang]

I am using snapshot build (the latest BeagleBone snapshot build:
FreeBSD-11.0-CURRENT-arm-armv6-BEAGLEBONE-20140323-r263665.img

Everytime I do reboot or poweroff, I get the captioned error. I googled 
it, I think I am not alone.

Also, I have the same problem with portsnap fetch.

Any idea how to fix it? Thanks.

Below is the log from BeagleBone Black UART:

root at beaglebone:~ # reboot
Mar 24 09:22:54 beaglebone reboot: rebooted by root
Mar 24 09:22:54 beaglebone syslogd: exiting on signal 15
Waiting (max 60 seconds) for system process `vnlru' to stop...done
Waiting (max 60 seconds) for system process `bufdaemon' to stop...done
Waiting (max 60 seconds) for system process `syncer' to stop...
Syncing disks, vnodes remaining...5 5 3 3 0 0 done
All buffers synced.
lock order reversal:
  1st 0xc2b97934 ufs (ufs) @ /usr/src/sys/kern/vfs_mount.c:1237
  2nd 0xc2b97814 devfs (devfs) @ /usr/src/sys/ufs/ffs/ffs_vfsops.c:1412
KDB: stack backtrace:
db_trace_self() at db_trace_self
          pc = 0xc0541754  lr = 0xc02324b8 (db_trace_self_wrapper+0x30)
          sp = 0xde6cc9c0  fp = 0xde6ccad8
         r10 = 0xc2b97814
db_trace_self_wrapper() at db_trace_self_wrapper+0x30
          pc = 0xc02324b8  lr = 0xc039b1a4 (kdb_backtrace+0x38)
          sp = 0xde6ccae0  fp = 0xde6ccae8
          r4 = 0xc0685484  r5 = 0xc0591b55
          r6 = 0xc05c3999  r7 = 0xc05b0bdc
kdb_backtrace() at kdb_backtrace+0x38
          pc = 0xc039b1a4  lr = 0xc03b5ad4 (witness_checkorder+0xe50)
          sp = 0xde6ccaf0  fp = 0xde6ccb40
          r4 = 0xc059d070
witness_checkorder() at witness_checkorder+0xe50
          pc = 0xc03b5ad4  lr = 0xc03480e8 (__lockmgr_args+0x8b4)
          sp = 0xde6ccb48  fp = 0xde6ccbb0
          r4 = 0x00000000  r5 = 0x00080400
          r6 = 0x00000584  r7 = 0xc2b97834
          r8 = 0xc2b97814  r9 = 0x00080000
         r10 = 0xc05c3996
__lockmgr_args() at __lockmgr_args+0x8b4
          pc = 0xc03480e8  lr = 0xc03fa264 (vop_stdlock+0x3c)
          sp = 0xde6ccbb8  fp = 0xde6ccbc8
          r4 = 0xde6ccbe8  r5 = 0xc065d020
          r6 = 0x00000000  r7 = 0x00080400
          r8 = 0xde6ccbe8  r9 = 0x00000000
         r10 = 0x00000584
vop_stdlock() at vop_stdlock+0x3c
          pc = 0xc03fa264  lr = 0xc056a790 (VOP_LOCK1_APV+0xd8)
          sp = 0xde6ccbd0  fp = 0xde6ccbe0
VOP_LOCK1_APV() at VOP_LOCK1_APV+0xd8
          pc = 0xc056a790  lr = 0xc04186c0 (_vn_lock+0x44)
          sp = 0xde6ccbe8  fp = 0xde6ccc18
          r4 = 0xc2b977e0  r5 = 0x0000000a
          r6 = 0xc05c3996
_vn_lock() at _vn_lock+0x44
          pc = 0xc04186c0  lr = 0xc04f2c40 (ffs_flushfiles+0x98)
          sp = 0xde6ccc20  fp = 0xde6ccc48
          r4 = 0xc2aaf900  r5 = 0x0000000a
          r6 = 0xc2aa3560  r7 = 0x00000000
          r8 = 0xc2e05640  r9 = 0x00000000
         r10 = 0x00000000
ffs_flushfiles() at ffs_flushfiles+0x98
          pc = 0xc04f2c40  lr = 0xc04d5e10 (softdep_flushfiles+0x1d0)
          sp = 0xde6ccc50  fp = 0xde6ccc98
          r4 = 0xc2aa3560  r5 = 0x0000000a
          r6 = 0xc2e05640  r7 = 0x00000000
          r8 = 0x00000100  r9 = 0xc05c382e
softdep_flushfiles() at softdep_flushfiles+0x1d0
          pc = 0xc04d5e10  lr = 0xc04f5960 (ffs_unmount+0x104)
          sp = 0xde6ccca0  fp = 0xde6cccd0
          r4 = 0xc2e05640  r5 = 0xc2c0a000
          r6 = 0x00000000  r7 = 0x00000000
          r8 = 0xc2e05640  r9 = 0x00000000
         r10 = 0xc2aaf900
ffs_unmount() at ffs_unmount+0x104
          pc = 0xc04f5960  lr = 0xc04026f8 (dounmount+0x4c4)
          sp = 0xde6cccd8  fp = 0xde6ccd20
          r4 = 0xc2b97900  r5 = 0x00000000
          r6 = 0x00000000  r7 = 0x00000000
          r8 = 0xc2e05640  r9 = 0x00080000
         r10 = 0x00080000
dounmount() at dounmount+0x4c4
          pc = 0xc04026f8  lr = 0xc040aea4 (vfs_unmountall+0x48)
          sp = 0xde6ccd28  fp = 0xde6ccd48
          r4 = 0xc2e05640  r5 = 0xc059d070
          r6 = 0x00000000  r7 = 0xc2aa3560
          r8 = 0xc065d2b0  r9 = 0xc05be5d0
         r10 = 0xc05b1c05
vfs_unmountall() at vfs_unmountall+0x48
          pc = 0xc040aea4  lr = 0xc0363fe4 (kern_reboot+0x47c)
          sp = 0xde6ccd50  fp = 0xde6ccdb0
          r4 = 0xc06691e4  r5 = 0xc092aad8
          r6 = 0x00000000  r7 = 0xcd2156a8
          r8 = 0xc05a165f  r9 = 0x00000000
         r10 = 0xc05a161e
kern_reboot() at kern_reboot+0x47c
          pc = 0xc0363fe4  lr = 0xc0363b60 ($d)
          sp = 0xde6ccdb8  fp = 0xde6ccdc0
          r4 = 0xde6cce20  r5 = 0xc2a9dc80
          r6 = 0x00000000  r7 = 0x00000000
          r8 = 0x00000000  r9 = 0xde6cce18
         r10 = 0x00000004
$d() at $d
          pc = 0xc0363b60  lr = 0xc05569f8 (swi_handler+0x284)
          sp = 0xde6ccdc8  fp = 0xde6cce60
          r4 = 0xc2e05640
swi_handler() at swi_handler+0x284
          pc = 0xc05569f8  lr = 0xc0543270 (swi_exit)
          sp = 0xde6cce68  fp = 0xbffffd08
          r4 = 0x00000004  r5 = 0x00000002
          r6 = 0xbffffce4  r7 = 0x00000037
          r8 = 0x00000000  r9 = 0x00000000
swi_exit() at swi_exit
          pc = 0xc0543270  lr = 0xc0543270 (swi_exit)
          sp = 0xde6cce68  fp = 0xbffffd08
Unable to unwind further
Uptime: 56s
Rebooting...


-- 
Thanks,
Xuebing Wang