Hello Robert, Zhu & Co, Thanks for your detailed bug report. Comments inline below. On Mon, 2016-10-17 at 22:42 -0600, Robert LeBlanc wrote: > Sorry I forget that Android has an aversion to plain text emails. > > If we can provide any information to help, let us know. We are willing > to patch in more debug statements or whatever you think might help. > Today has been a difficult day. Thanks for looking into it, I tried > looking at it, but it is way over my head. > > ---------------- > Robert LeBlanc > PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 > > > On Mon, Oct 17, 2016 at 9:06 PM, Zhu Lingshan <lszhu@xxxxxxxx> wrote: > > Hi Robert, > > > > I think the reason why you can not logout the targets is that iscsi_np in D > > status. I think the patches fixed something, but it seems to be more than > > one code path can trigger these similar issues. as you can see, there are > > several call stacks, I am still working on it. Actually in my environment I > > see there is another call stack not listed in your mail.... > > > > Thanks, > > BR > > Zhu Lingshan > > > > > > On 10/18/2016 03:11 AM, Robert LeBlanc wrote: > >> > >> Sorry hit send too soon. > >> > >> In addition, on the client we see: > >> # ps -aux | grep D | grep kworker > >> root 5583 0.0 0.0 0 0 ? D 11:55 0:03 > >> [kworker/11:0] > >> root 7721 0.1 0.0 0 0 ? D 12:00 0:04 > >> [kworker/4:25] > >> root 10877 0.0 0.0 0 0 ? D 09:27 0:00 > >> [kworker/22:1] > >> root 11246 0.0 0.0 0 0 ? D 10:28 0:00 > >> [kworker/30:2] > >> root 14034 0.0 0.0 0 0 ? D 12:20 0:02 > >> [kworker/19:15] > >> root 14048 0.0 0.0 0 0 ? D 12:20 0:00 > >> [kworker/16:0] > >> root 15871 0.0 0.0 0 0 ? D 12:25 0:00 > >> [kworker/13:0] > >> root 17442 0.0 0.0 0 0 ? D 12:28 0:00 > >> [kworker/9:1] > >> root 17816 0.0 0.0 0 0 ? D 12:30 0:00 > >> [kworker/11:1] > >> root 18744 0.0 0.0 0 0 ? D 12:32 0:00 > >> [kworker/10:2] > >> root 19060 0.0 0.0 0 0 ? D 12:32 0:00 > >> [kworker/29:0] > >> root 21748 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/21:0] > >> root 21967 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/22:0] > >> root 21978 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/22:2] > >> root 22024 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/22:4] > >> root 22035 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/22:5] > >> root 22060 0.0 0.0 0 0 ? D 12:40 0:00 > >> [kworker/16:1] > >> root 22282 0.0 0.0 0 0 ? D 12:41 0:00 > >> [kworker/26:0] > >> root 22362 0.0 0.0 0 0 ? D 12:42 0:00 > >> [kworker/18:9] > >> root 22426 0.0 0.0 0 0 ? D 12:42 0:00 > >> [kworker/16:3] > >> root 23298 0.0 0.0 0 0 ? D 12:43 0:00 > >> [kworker/12:1] > >> root 23302 0.0 0.0 0 0 ? D 12:43 0:00 > >> [kworker/12:5] > >> root 24264 0.0 0.0 0 0 ? D 12:46 0:00 > >> [kworker/30:1] > >> root 24271 0.0 0.0 0 0 ? D 12:46 0:00 > >> [kworker/14:8] > >> root 24441 0.0 0.0 0 0 ? D 12:47 0:00 > >> [kworker/9:7] > >> root 24443 0.0 0.0 0 0 ? D 12:47 0:00 > >> [kworker/9:9] > >> root 25005 0.0 0.0 0 0 ? D 12:48 0:00 > >> [kworker/30:3] > >> root 25158 0.0 0.0 0 0 ? D 12:49 0:00 > >> [kworker/9:12] > >> root 26382 0.0 0.0 0 0 ? D 12:52 0:00 > >> [kworker/13:2] > >> root 26453 0.0 0.0 0 0 ? D 12:52 0:00 > >> [kworker/21:2] > >> root 26724 0.0 0.0 0 0 ? D 12:53 0:00 > >> [kworker/19:1] > >> root 28400 0.0 0.0 0 0 ? D 05:20 0:00 > >> [kworker/25:1] > >> root 29552 0.0 0.0 0 0 ? D 11:40 0:00 > >> [kworker/17:1] > >> root 29811 0.0 0.0 0 0 ? D 11:40 0:00 > >> [kworker/7:10] > >> root 31903 0.0 0.0 0 0 ? D 11:43 0:00 > >> [kworker/26:1] > >> > >> And all of the processes have this stack: > >> [<ffffffffa0727ed5>] iser_release_work+0x25/0x60 [ib_iser] > >> [<ffffffff8109633f>] process_one_work+0x14f/0x400 > >> [<ffffffff81096bb4>] worker_thread+0x114/0x470 > >> [<ffffffff8109c6f8>] kthread+0xd8/0xf0 > >> [<ffffffff8172004f>] ret_from_fork+0x3f/0x70 > >> [<ffffffffffffffff>] 0xffffffffffffffff > >> > >> We are not able to log out of the sessions in all cases. And have to > >> restart the box. > >> > >> iscsiadm -m session will show messages like: > >> iscsiadm: could not read session targetname: 5 > >> iscsiadm: could not find session info for session100 > >> iscsiadm: could not read session targetname: 5 > >> iscsiadm: could not find session info for session101 > >> iscsiadm: could not read session targetname: 5 > >> iscsiadm: could not find session info for session103 > >> ... > >> > >> I can't find any way to force iscsiadm to clean up these sessions > >> possibly due to tasks in D state. > >> ---------------- > >> Robert LeBlanc > >> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 > >> > >> > >> On Mon, Oct 17, 2016 at 10:32 AM, Robert LeBlanc <robert@xxxxxxxxxxxxx> > >> wrote: > >>> > >>> Some more info as we hit this this morning. We have volumes mirrored > >>> between two targets and we had one target on the kernel with the three > >>> patches mentioned in this thread [0][1][2] and the other was on a > >>> kernel without the patches. We decided that after a week and a half we > >>> wanted to get both targets on the same kernel so we rebooted the > >>> non-patched target. Within an hour we saw iSCSI in D state with the > >>> same stack trace so it seems that we are not hitting any of the > >>> WARN_ON lines. We are getting both iscsi_trx and iscsi_np both in D > >>> state, this time we have two iscsi_trx processes in D state. I don't > >>> know if stale sessions on the clients could be contributing to this > >>> issue (the target trying to close non-existent sessions??). This is on > >>> 4.4.23. Any more debug info we can throw at this problem to help? > >>> > >>> Thank you, > >>> Robert LeBlanc > >>> > >>> # ps aux | grep D | grep iscsi > >>> root 16525 0.0 0.0 0 0 ? D 08:50 0:00 > >>> [iscsi_np] > >>> root 16614 0.0 0.0 0 0 ? D 08:50 0:00 > >>> [iscsi_trx] > >>> root 16674 0.0 0.0 0 0 ? D 08:50 0:00 > >>> [iscsi_trx] > >>> > >>> # for i in 16525 16614 16674; do echo $i; cat /proc/$i/stack; done > >>> 16525 > >>> [<ffffffff814f0d5f>] iscsit_stop_session+0x19f/0x1d0 > >>> [<ffffffff814e2516>] iscsi_check_for_session_reinstatement+0x1e6/0x270 > >>> [<ffffffff814e4ed0>] iscsi_target_check_for_existing_instances+0x30/0x40 > >>> [<ffffffff814e5020>] iscsi_target_do_login+0x140/0x640 > >>> [<ffffffff814e63bc>] iscsi_target_start_negotiation+0x1c/0xb0 > >>> [<ffffffff814e410b>] iscsi_target_login_thread+0xa9b/0xfc0 > >>> [<ffffffff8109c748>] kthread+0xd8/0xf0 > >>> [<ffffffff8172018f>] ret_from_fork+0x3f/0x70 > >>> [<ffffffffffffffff>] 0xffffffffffffffff > >>> 16614 > >>> [<ffffffff814cca79>] target_wait_for_sess_cmds+0x49/0x1a0 > >>> [<ffffffffa064692b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert] > >>> [<ffffffff814f0ef2>] iscsit_close_connection+0x162/0x870 > >>> [<ffffffff814df9bf>] iscsit_take_action_for_connection_exit+0x7f/0x100 > >>> [<ffffffff814f00a0>] iscsi_target_rx_thread+0x5a0/0xe80 > >>> [<ffffffff8109c748>] kthread+0xd8/0xf0 > >>> [<ffffffff8172018f>] ret_from_fork+0x3f/0x70 > >>> [<ffffffffffffffff>] 0xffffffffffffffff > >>> 16674 > >>> [<ffffffff814cca79>] target_wait_for_sess_cmds+0x49/0x1a0 > >>> [<ffffffffa064692b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert] > >>> [<ffffffff814f0ef2>] iscsit_close_connection+0x162/0x870 > >>> [<ffffffff814df9bf>] iscsit_take_action_for_connection_exit+0x7f/0x100 > >>> [<ffffffff814f00a0>] iscsi_target_rx_thread+0x5a0/0xe80 > >>> [<ffffffff8109c748>] kthread+0xd8/0xf0 > >>> [<ffffffff8172018f>] ret_from_fork+0x3f/0x70 > >>> [<ffffffffffffffff>] 0xffffffffffffffff > >>> > >>> > >>> [0] https://www.spinics.net/lists/target-devel/msg13463.html > >>> [1] http://marc.info/?l=linux-scsi&m=147282568910535&w=2 > >>> [2] http://www.spinics.net/lists/linux-scsi/msg100221.html The call chain above is iscsi session reinstatement driven by open-iscsi/iser resulting in target-core to sleep indefinitely, waiting for outstanding target-core backend driver se_cmd I/O to complete in order to make forward progress. Note, there is a v4.1+ se_cmd->cmd_kref reference leak bug for TMR ABORT_TASK during simultaneous target back-end I/O completion timeouts here: http://www.spinics.net/lists/target-devel/msg13530.html If you are actively observing TMR ABORT_TASK preceding the hung task timeout warnings above with v4.4.y + v4.2.y iser-target exports, then it's likely the same bug. Please apply the patch on your v4.x setup to verify. If no TMR ABORT_TASK timeouts + session reinstatements are occurring on your iser-target setup, then it is a separate bug. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
