Same here, md raid10 (not sure if its important but xfs, hung 3 times in last 2 days).
It seems that a combination of md raid10 check + I/O (maybe XFS-specific, I dunno, but both original poster and us seem to use XFS) frequently hangs on kernels that are newer than Ubuntu 4.10.0-42.46~16.04.1-generic 4.10.17 (yes, I know it's a wide range, but everything started happening after we rebooted this machine, which upgraded us from Ubuntu 4.10.0-42.46~16.04.1-generic 4.10.17 to Ubuntu 4.13.0-43.48~16.04.1-generic 4.13.16, the check was scheduled some time later, so we didn't catch it immediately).

The logs look very similar:
Jun 13 19:15:42 pisces kernel: [27430.370899] INFO: task md7_resync:12982 blocked for more than 120 seconds.
Jun 13 19:15:42 pisces kernel: [27430.370940]       Not tainted 4.13.0-43-generic #48~16.04.1-Ubuntu
Jun 13 19:15:42 pisces kernel: [27430.370966] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 13 19:15:42 pisces kernel: [27430.370997] md7_resync      D    0 12982      2 0x80000000
Jun 13 19:15:42 pisces kernel: [27430.371000] Call Trace:
Jun 13 19:15:42 pisces kernel: [27430.371012]  __schedule+0x3d6/0x8b0
Jun 13 19:15:42 pisces kernel: [27430.371014]  schedule+0x36/0x80
Jun 13 19:15:42 pisces kernel: [27430.371020]  raise_barrier+0xd2/0x1a0 [raid10]
Jun 13 19:15:42 pisces kernel: [27430.371024]  ? wait_woken+0x80/0x80
Jun 13 19:15:42 pisces kernel: [27430.371027]  raid10_sync_request+0x9bd/0x1b10 [raid10]
Jun 13 19:15:42 pisces kernel: [27430.371031]  ? pick_next_task_fair+0x449/0x570
Jun 13 19:15:42 pisces kernel: [27430.371035]  ? __switch_to+0xb2/0x540
Jun 13 19:15:42 pisces kernel: [27430.371041]  ? find_next_bit+0xb/0x10
Jun 13 19:15:42 pisces kernel: [27430.371046]  ? is_mddev_idle+0xa1/0x101
Jun 13 19:15:42 pisces kernel: [27430.371048]  md_do_sync+0xb81/0xfb0
Jun 13 19:15:42 pisces kernel: [27430.371050]  ? wait_woken+0x80/0x80
Jun 13 19:15:42 pisces kernel: [27430.371054]  md_thread+0x133/0x180
Jun 13 19:15:42 pisces kernel: [27430.371055]  ? md_thread+0x133/0x180
Jun 13 19:15:42 pisces kernel: [27430.371060]  kthread+0x10c/0x140
Jun 13 19:15:42 pisces kernel: [27430.371062]  ? state_show+0x320/0x320
Jun 13 19:15:42 pisces kernel: [27430.371064]  ? kthread_create_on_node+0x70/0x70
Jun 13 19:15:42 pisces kernel: [27430.371067]  ret_from_fork+0x35/0x40
Jun 13 19:15:42 pisces kernel: [27430.371181] INFO: task kworker/20:1:27873 blocked for more than 120 seconds.
Jun 13 19:15:42 pisces kernel: [27430.371210]       Not tainted 4.13.0-43-generic #48~16.04.1-Ubuntu
Jun 13 19:15:42 pisces kernel: [27430.371235] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 13 19:15:42 pisces kernel: [27430.371267] kworker/20:1    D    0 27873      2 0x80000000
Jun 13 19:15:42 pisces kernel: [27430.371333] Workqueue: xfs-sync/md7 xfs_log_worker [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371334] Call Trace:
Jun 13 19:15:42 pisces kernel: [27430.371338]  __schedule+0x3d6/0x8b0
Jun 13 19:15:42 pisces kernel: [27430.371340]  schedule+0x36/0x80
Jun 13 19:15:42 pisces kernel: [27430.371342]  schedule_timeout+0x1f3/0x360
Jun 13 19:15:42 pisces kernel: [27430.371347]  ? scsi_init_rq+0x84/0x100
Jun 13 19:15:42 pisces kernel: [27430.371349]  wait_for_completion+0xb4/0x140
Jun 13 19:15:42 pisces kernel: [27430.371351]  ? wait_for_completion+0xb4/0x140
Jun 13 19:15:42 pisces kernel: [27430.371356]  ? wake_up_q+0x70/0x70
Jun 13 19:15:42 pisces kernel: [27430.371360]  flush_work+0x129/0x1e0
Jun 13 19:15:42 pisces kernel: [27430.371363]  ? worker_detach_from_pool+0xb0/0xb0
Jun 13 19:15:42 pisces kernel: [27430.371397]  xlog_cil_force_lsn+0x8b/0x220 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371400]  ? update_curr+0x138/0x1d0
Jun 13 19:15:42 pisces kernel: [27430.371433]  _xfs_log_force+0x85/0x290 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371436]  ? pick_next_task_fair+0x131/0x570
Jun 13 19:15:42 pisces kernel: [27430.371438]  ? __switch_to+0xb2/0x540
Jun 13 19:15:42 pisces kernel: [27430.371471]  ? xfs_log_worker+0x36/0x100 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371505]  xfs_log_force+0x2c/0x80 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371538]  xfs_log_worker+0x36/0x100 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371541]  process_one_work+0x15b/0x410
Jun 13 19:15:42 pisces kernel: [27430.371544]  worker_thread+0x4b/0x460
Jun 13 19:15:42 pisces kernel: [27430.371546]  kthread+0x10c/0x140
Jun 13 19:15:42 pisces kernel: [27430.371548]  ? process_one_work+0x410/0x410
Jun 13 19:15:42 pisces kernel: [27430.371550]  ? kthread_create_on_node+0x70/0x70
Jun 13 19:15:42 pisces kernel: [27430.371552]  ret_from_fork+0x35/0x40
Jun 13 19:15:42 pisces kernel: [27430.371557] INFO: task kworker/20:0:4504 blocked for more than 120 seconds.
Jun 13 19:15:42 pisces kernel: [27430.371587]       Not tainted 4.13.0-43-generic #48~16.04.1-Ubuntu
Jun 13 19:15:42 pisces kernel: [27430.371611] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 13 19:15:42 pisces kernel: [27430.371642] kworker/20:0    D    0  4504      2 0x80000000
Jun 13 19:15:42 pisces kernel: [27430.371680] Workqueue: xfs-cil/md7 xlog_cil_push_work [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371681] Call Trace:
Jun 13 19:15:42 pisces kernel: [27430.371684]  __schedule+0x3d6/0x8b0
Jun 13 19:15:42 pisces kernel: [27430.371687]  schedule+0x36/0x80
Jun 13 19:15:42 pisces kernel: [27430.371689]  md_flush_request+0x6e/0x130
Jun 13 19:15:42 pisces kernel: [27430.371691]  ? wait_woken+0x80/0x80
Jun 13 19:15:42 pisces kernel: [27430.371694]  raid10_make_request+0x12a/0x130 [raid10]
Jun 13 19:15:42 pisces kernel: [27430.371696]  md_handle_request+0xb5/0x130
Jun 13 19:15:42 pisces kernel: [27430.371698]  md_make_request+0x6c/0x170
Jun 13 19:15:42 pisces kernel: [27430.371702]  generic_make_request+0x12a/0x300
Jun 13 19:15:42 pisces kernel: [27430.371704]  submit_bio+0x73/0x150
Jun 13 19:15:42 pisces kernel: [27430.371706]  ? submit_bio+0x73/0x150
Jun 13 19:15:42 pisces kernel: [27430.371737]  _xfs_buf_ioapply+0x2e7/0x4a0 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371741]  ? kernel_fpu_end+0xe/0x10
Jun 13 19:15:42 pisces kernel: [27430.371775]  ? xlog_bdstrat+0x2b/0x60 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371807]  xfs_buf_submit+0x63/0x210 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371838]  ? xfs_buf_submit+0x63/0x210 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371872]  xlog_bdstrat+0x2b/0x60 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371907]  xlog_sync+0x2c1/0x3c0 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371949]  xlog_state_release_iclog+0x76/0xc0 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.371985]  xlog_write+0x55c/0x720 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.372020]  xlog_cil_push+0x22b/0x3f0 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.372054]  xlog_cil_push_work+0x15/0x20 [xfs]
Jun 13 19:15:42 pisces kernel: [27430.372057]  process_one_work+0x15b/0x410
Jun 13 19:15:42 pisces kernel: [27430.372059]  worker_thread+0x22b/0x460
Jun 13 19:15:42 pisces kernel: [27430.372061]  kthread+0x10c/0x140
Jun 13 19:15:42 pisces kernel: [27430.372063]  ? process_one_work+0x410/0x410
Jun 13 19:15:42 pisces kernel: [27430.372065]  ? kthread_create_on_node+0x70/0x70
Jun 13 19:15:42 pisces kernel: [27430.372067]  ret_from_fork+0x35/0x40
...