Comment 27 for bug 681083

I dont know if its the same bugs or another bug here its the stack trace on the ocasional failures:

[6368472.738379] Call Trace:
[6368472.738389] [<ffffffff81041abe>] ? pick_next_task_fair+0xca/0xd6
[6368472.738395] [<ffffffff812fae40>] ? thread_return+0x79/0xe0
[6368472.738401] [<ffffffff8100e160>] ? xen_vcpuop_set_next_event+0x0/0x60
[6368472.738405] [<ffffffff812fb1fd>] ? schedule_timeout+0x2e/0xdd
[6368472.738408] [<ffffffff8100e22f>] ? xen_restore_fl_direct_end+0x0/0x1
[6368472.738412] [<ffffffff812fc1da>] ? _spin_unlock_irqrestore+0xd/0xe
[6368472.738418] [<ffffffff810ad168>] ? cpupri_set+0x10c/0x135
[6368472.738425] [<ffffffff8121cc16>] ? serial8250_resume+0x0/0x3a
[6368472.738428] [<ffffffff812fb0b4>] ? wait_for_common+0xde/0x15b
[6368472.738433] [<ffffffff8104a42f>] ? default_wake_function+0x0/0x9
[6368472.738439] [<ffffffff81061b0c>] ? flush_cpu_workqueue+0x5e/0x75
[6368472.738442] [<ffffffff81064c2e>] ? kthread_stop+0x5d/0xa2
[6368472.738446] [<ffffffff81061b67>] ? cleanup_workqueue_thread+0x44/0x51
[6368472.738449] [<ffffffff81061c0e>] ? destroy_workqueue+0x76/0xad
[6368472.738454] [<ffffffff8108ad7f>] ? stop_machine_destroy+0x2e/0x47
[6368472.738458] [<ffffffff811efd2d>] ? shutdown_handler+0x230/0x25c
[6368472.738462] [<ffffffff812fb776>] ? mutex_lock+0xd/0x31
[6368472.738465] [<ffffffff811f1038>] ? xenwatch_thread+0x117/0x14a
[6368472.738469] [<ffffffff81064e96>] ? autoremove_wake_function+0x0/0x2e
[6368472.738472] [<ffffffff811f0f21>] ? xenwatch_thread+0x0/0x14a
[6368472.738474] [<ffffffff81064bc9>] ? kthread+0x79/0x81
[6368472.738479] [<ffffffff81011baa>] ? child_rip+0xa/0x20
[6368472.738482] [<ffffffff81010d61>] ? int_ret_from_sys_call+0x7/0x1b
[6368472.738485] [<ffffffff8101151d>] ? retint_restore_args+0x5/0x6
[6368472.738489] [<ffffffff8100e22f>] ? xen_restore_fl_direct_end+0x0/0x1
[6368472.738492] [<ffffffff81011ba0>] ? child_rip+0x0/0x20

But after some time it gets back to normal.