Kernel BUG at ctree.c:1144 and soft lockup while defragging

Kernel BUG at ctree.c:1144 and soft lockup while defragging

[Szőts Ákos]

Dear list,

While I was trying to defrag a specified directory I got kernel BUGs and 
warnings about CPUx stucked for twenty-some seconds.

The specified warnings were:
BUG at ctree.c:1144. Invalid opcode: 0000
command: btrfs-endio-wri
Call trace top: btrfs_search_old_slot

The executed command in $HOME/.local:
find -xdev -type f -exec btrfs fi defrag -clzo '{}' \;

After that a soft lockup BUG occurred with systemd-journal with 
btrfs_add_delayed_data_ref being on top of the call trace.

Since no log stayed in the journal, I took some pictures and uploaded them 
here:
- Ctree bug: www.morrohun.hu/temp/btrfs/IMG_1983.JPG
                  www.morrohun.hu/temp/btrfs/IMG_1985.JPG
- Soft lockup with systemd-journal: www.morrohun.hu/temp/btrfs/IMG_1995.JPG
- Same stack trace without lockup and with btrfs-endio-wri: 
www.morrohun.hu/temp/btrfs/IMG_1996.JPG

System: openSUSE 12.3, kernel 3.9.2-3.g97197ff-desktop.

If you need an image, can I take a snapshot just from the specified directory?

Best regards,

Ákos Szőts