"nbd0: Attempted send on closed socket" Trying to shut off thin clients from loggin screen fails

[john]

I am using edubuntu Hardy with  6030 series thin clients purchased
from Devon IT. When a teacher try's to turn of the thin client at the
end of the day by logging out and going to Preferences>Shutdown the
thin client doesn't shutdown. It won't reboot either. These messages
appear in /var/log/kern.log

The clients need a hard reboot or power down.

Is this a known bug?

excerpt from kern.log follows

Thanks!

John


Sep 10 08:21:40 192.168.0.236 kernel: [761213.847481] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.847509] end_request: I/O
error, dev nbd0, sector 93308
Sep 10 08:21:40 192.168.0.236 kernel: [761213.849642] SQUASHFS error:
sb_bread failed reading block 0xb66c
Sep 10 08:21:40 192.168.0.236 kernel: [761213.849661] SQUASHFS error:
Unable to read fragment cache block [2d8f89c]
Sep 10 08:21:40 192.168.0.236 kernel: [761213.849673] SQUASHFS error:
Unable to read page, block 2d8f89c, size ba8f
Sep 10 08:21:40 192.168.0.236 kernel: [761213.853110] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.853127] end_request: I/O
error, dev nbd0, sector 93308
Sep 10 08:21:40 192.168.0.236 kernel: [761213.855131] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.855150] end_request: I/O
error, dev nbd0, sector 93310
Sep 10 08:21:40 192.168.0.236 kernel: [761213.856969] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.856984] end_request: I/O
error, dev nbd0, sector 93312
Sep 10 08:21:40 192.168.0.236 kernel: [761213.858832] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.858847] end_request: I/O
error, dev nbd0, sector 93314
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860851] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860870] end_request: I/O
error, dev nbd0, sector 93316
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860893] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860901] end_request: I/O
error, dev nbd0, sector 93318
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860916] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860923] end_request: I/O
error, dev nbd0, sector 93320
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860938] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860946] end_request: I/O
error, dev nbd0, sector 93322
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860960] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860968] end_request: I/O
error, dev nbd0, sector 93324
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860982] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.860990] end_request: I/O
error, dev nbd0, sector 93326
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861004] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861011] end_request: I/O
error, dev nbd0, sector 93328
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861026] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861033] end_request: I/O
error, dev nbd0, sector 93330
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861047] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861055] end_request: I/O
error, dev nbd0, sector 93332
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861069] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861077] end_request: I/O
error, dev nbd0, sector 93334
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861092] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861099] end_request: I/O
error, dev nbd0, sector 93336
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861113] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861121] end_request: I/O
error, dev nbd0, sector 93338
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861135] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861143] end_request: I/O
error, dev nbd0, sector 93340
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861157] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861165] end_request: I/O
error, dev nbd0, sector 93342
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861179] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861187] end_request: I/O
error, dev nbd0, sector 93344
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861201] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861208] end_request: I/O
error, dev nbd0, sector 93346
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861222] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861230] end_request: I/O
error, dev nbd0, sector 93348
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861244] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861252] end_request: I/O
error, dev nbd0, sector 93350
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861266] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861274] end_request: I/O
error, dev nbd0, sector 93352
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861288] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861296] end_request: I/O
error, dev nbd0, sector 93354
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861310] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861318] end_request: I/O
error, dev nbd0, sector 93356
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861332] nbd0: Attempted
send on closed socket
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861339] end_request: I/O
error, dev nbd0, sector 93358
Sep 10 08:21:40 192.168.0.236 kernel: [761213.861354] nbd0: Attempted
send on closed socket