/ # rm -rf /mnt/btr/var_tmp/paludis/dev-lang-jhc-9999/
[   50.680000] Kernel panic - not syncing: Kernel mode signal 4
[   50.680000] Call Trace: 
[   50.680000] 6023d918:  [<601a2342>] panic+0xea/0x1dc
[   50.680000] 6023d938:  [<6001c4a1>] ubd_intr+0x6d/0xc9
[   50.680000] 6023d978:  [<6004d5a9>] handle_irq_event_percpu+0x10a/0x126
[   50.680000] 6023d9c8:  [<6004d5e8>] handle_irq_event+0x23/0x2f
[   50.680000] 6023d9e8:  [<60018092>] free_irqs+0x72/0xdc
[   50.680000] 6023da18:  [<60016aa3>] relay_signal+0x38/0x79
[   50.680000] 6023da28:  [<600140d1>] sigio_handler+0x5a/0x5f
[   50.680000] 6023da48:  [<6001fc2d>] sig_handler_common+0x87/0x9b
[   50.680000] 6023da68:  [<6001fc7d>] real_alarm_handler+0x3c/0x3e
[   50.680000] 6023daf0:  [<6006cdab>] kernel_map_pages+0x73/0x18c
[   50.680000] 6023db78:  [<6001fd22>] sig_handler+0x30/0x3e
[   50.680000] 6023db98:  [<6001f93e>] handle_signal+0x72/0xa8
[   50.680000] 6023dbe8:  [<60020b3c>] hard_handler+0x10/0x14
[   50.680000] 6023dca8:  [<600d4985>] btrfs_unlink+0x75/0xbc
[   50.680000] 
[   50.680000] 
[   50.680000] Pid: 1, comm: busybox Not tainted 2.6.39-rc3
[   50.680000] RIP: 0033:[<00000000005443a7>]
[   50.680000] RSP: 0000007fbfe894f8  EFLAGS: 00000246
[   50.680000] RAX: ffffffffffffffda RBX: 00000000008536a0 RCX: ffffffffffffffff
[   50.680000] RDX: 0000007fbfe89500 RSI: 0000007fbfe89500 RDI: 00000000008536a0
[   50.680000] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[   50.680000] R10: 7263616d2d63612f R11: 0000000000000246 R12: 0000000000000000
[   50.680000] R13: 0000000040001010 R14: 00000000008536a0 R15: 00000000ffffffff
[   50.680000] Call Trace: 
[   50.680000] 6023d898:  [<60016c99>] panic_exit+0x2f/0x45
[   50.680000] 6023d8b8:  [<600429ad>] notifier_call_chain+0x5f/0x96
[   50.680000] 6023d908:  [<60042a83>] atomic_notifier_call_chain+0xf/0x11
[   50.680000] 6023d918:  [<601a235d>] panic+0x105/0x1dc
[   50.680000] 6023d938:  [<6001c4a1>] ubd_intr+0x6d/0xc9
[   50.680000] 6023d978:  [<6004d5a9>] handle_irq_event_percpu+0x10a/0x126
[   50.680000] 6023d9c8:  [<6004d5e8>] handle_irq_event+0x23/0x2f
[   50.680000] 6023d9e8:  [<60018092>] free_irqs+0x72/0xdc
[   50.680000] 6023da18:  [<60016aa3>] relay_signal+0x38/0x79
[   50.680000] 6023da28:  [<600140d1>] sigio_handler+0x5a/0x5f
[   50.680000] 6023da48:  [<6001fc2d>] sig_handler_common+0x87/0x9b
[   50.680000] 6023da68:  [<6001fc7d>] real_alarm_handler+0x3c/0x3e
[   50.680000] 6023daf0:  [<6006cdab>] kernel_map_pages+0x73/0x18c
[   50.680000] 6023db78:  [<6001fd22>] sig_handler+0x30/0x3e
[   50.680000] 6023db98:  [<6001f93e>] handle_signal+0x72/0xa8
[   50.680000] 6023dbe8:  [<60020b3c>] hard_handler+0x10/0x14
[   50.680000] 6023dca8:  [<600d4985>] btrfs_unlink+0x75/0xbc
[   50.680000]