[  720.180047] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  720.180053] drbd0_worker  D ffff880003dce980     0  6636      2 0x00000000
[  720.180058]  ffff8801d68c1c10 0000000000000246 ffff880100000000 0000000000015980
[  720.180062]  ffff8801d68c1fd8 0000000000015980 ffff8801d68c1fd8 ffff8801d5a9adc0
[  720.180066]  0000000000015980 0000000000015980 ffff8801d68c1fd8 0000000000015980
[  720.180069] Call Trace:
[  720.180080]  [<ffffffff815a247d>] schedule_timeout+0x22d/0x310
[  720.180085]  [<ffffffff81006afd>] ? __raw_callee_save_xen_irq_disable+0x11/0x1e
[  720.180088]  [<ffffffff81006b1b>] ? __raw_callee_save_xen_irq_enable+0x11/0x26
[  720.180091]  [<ffffffff815a15f6>] wait_for_common+0xd6/0x180
[  720.180095]  [<ffffffff81056c10>] ? default_wake_function+0x0/0x20
[  720.180098]  [<ffffffff815a177d>] wait_for_completion+0x1d/0x20
[  720.180111]  [<ffffffffa000ad49>] drbd_bm_write_page+0xc9/0x1d0 [drbd]
[  720.180115]  [<ffffffff81006afd>] ? __raw_callee_save_xen_irq_disable+0x11/0x1e
[  720.180123]  [<ffffffffa0028515>] w_update_odbm+0x45/0x360 [drbd]
[  720.180129]  [<ffffffffa000da76>] drbd_worker+0x1f6/0x590 [drbd]
[  720.180135]  [<ffffffffa002d32c>] drbd_thread_setup+0xdc/0x2d0 [drbd]
[  720.180139]  [<ffffffff8100aee4>] kernel_thread_helper+0x4/0x10
[  720.180142]  [<ffffffff815a45dd>] ? retint_restore_args+0x5/0x6
[  720.180145]  [<ffffffff8100aee0>] ? kernel_thread_helper+0x0/0x10