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iscsi_trx going into D state

Message ID CAANLjFpSnQ7ApOK5HDRHXQQeQNGWLUv4e+2N=_e-zBeziYm5tw@mail.gmail.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Robert LeBlanc Jan. 3, 2017, 8:07 p.m. UTC
With this patch I'm not seeing the __ib_drain_sq backtraces, but I'm
still seeing the previous backtraces.


I was thinking that if the connection was brought down uncleanly then
there may be messages(??) it the send queue that would never be
consumed by the application, so it would never drain and would have to
be forcibly emptied. Maybe there is something stuck in the command
queue as well?

[(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
root     15426  0.0  0.0      0     0 ?        D    12:48   0:00 [iscsi_np]
root     15429  0.0  0.0      0     0 ?        D    12:48   0:00 [iscsi_ttx]
root     16077  0.0  0.0 112656  2216 pts/0    S+   12:55   0:00 grep
--color=auto  D
[(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15426/stack
[<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
[<ffffffff81521c62>] iscsi_check_for_session_reinstatement+0x1e2/0x270
[<ffffffff81524660>] iscsi_target_check_for_existing_instances+0x30/0x40
[<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
[<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
[<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
[<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
[<ffffffff810a3059>] kthread+0xd9/0xf0
[<ffffffff817732d5>] ret_from_fork+0x25/0x30
[<ffffffffffffffff>] 0xffffffffffffffff
[(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15429/stack
[<ffffffff8150c689>] target_wait_for_sess_cmds+0x49/0x190
[<ffffffffa0705744>] isert_wait_conn+0x1a4/0x2d0 [ib_isert]
[<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
[<ffffffff8151f10b>] iscsit_take_action_for_connection_exit+0x7b/0xf0
[<ffffffff81530150>] iscsi_target_tx_thread+0x150/0x1d0
[<ffffffff810a3059>] kthread+0xd9/0xf0
[<ffffffff817732d5>] ret_from_fork+0x25/0x30
[<ffffffffffffffff>] 0xffffffffffffffff
----------------
Robert LeBlanc
PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1


On Fri, Dec 30, 2016 at 4:07 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
> I decided to try something completely different... Running the stock
> CentOS 3.10 kernel and OFED 3.4 on both hosts, I'm not seeing the hung
> processes and the tests complete successfully. The same seems to be
> true for the target on 4.9 and the initiator on 3.10.
>
> However, with the target on 3.10 and the initiator on 4.9, I get this
> on the target:
>
> [(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
> root     14791  0.0  0.0      0     0 ?        D    15:08   0:00 [iscsi_np]
> root     14795  0.0  0.0      0     0 ?        D    15:08   0:00 [iscsi_trx]
> root     14852  0.0  0.0 112648   976 pts/0    S+   15:11   0:00 grep
> --color=auto  D
> [(support-1.0) root@prv-0-13-roberttest ~]# uname -a
> Linux prv-0-13-roberttest.betterservers.com 3.10.0-327.36.3.el7.x86_64
> #1 SMP Mon Oct 24 16:09:20 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14791/stack
> [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0 [iscsi_target_mod]
> [<ffffffffa09ceefa>] iscsi_check_for_session_reinstatement+0x1ea/0x280
> [iscsi_target_mod]
> [<ffffffffa09d19f5>]
> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
> [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670 [iscsi_target_mod]
> [<ffffffffa09d2f4c>] iscsi_target_start_negotiation+0x1c/0xb0 [iscsi_target_mod]
> [<ffffffffa09d0c6f>] iscsi_target_login_thread+0xadf/0x1050 [iscsi_target_mod]
> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> [<ffffffffffffffff>] 0xffffffffffffffff
> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14795/stack
> [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
> [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
> [<ffffffffa09ddfbd>] iscsit_close_connection+0x15d/0x820 [iscsi_target_mod]
> [<ffffffffa09cc183>] iscsit_take_action_for_connection_exit+0x83/0x110
> [iscsi_target_mod]
> [<ffffffffa09dccb7>] iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> [  345.970157] iSCSI Login timeout on Network Portal 0.0.0.0:3260
> [  483.850714] INFO: task iscsi_np:14791 blocked for more than 120 seconds.
> [  483.857467] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> disables this message.
> [  483.865326] iscsi_np        D 0000000000000000     0 14791      2 0x00000004
> [  483.872460]  ffff886e3b117be0 0000000000000046 ffff887ede579700
> ffff886e3b117fd8
> [  483.879983]  ffff886e3b117fd8 ffff886e3b117fd8 ffff887ede579700
> ffff883ef7898160
> [  483.887500]  ffff883ef7898168 7fffffffffffffff ffff887ede579700
> 0000000000000000
> [  483.895025] Call Trace:
> [  483.897505]  [<ffffffff8163bb39>] schedule+0x29/0x70
> [  483.902496]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
> [  483.908355]  [<ffffffff812fc60b>] ? simple_strtoull+0x3b/0x70
> [  483.914128]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
> [  483.920253]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
> [  483.925847]  [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0
> [iscsi_target_mod]
> [  483.933612]  [<ffffffffa09ceefa>]
> iscsi_check_for_session_reinstatement+0x1ea/0x280 [iscsi_target_mod]
> [  483.942944]  [<ffffffffa09d19f5>]
> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
> [  483.953304]  [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670
> [iscsi_target_mod]
> [  483.961988]  [<ffffffffa09d2f4c>]
> iscsi_target_start_negotiation+0x1c/0xb0 [iscsi_target_mod]
> [  483.971278]  [<ffffffffa09d0c6f>]
> iscsi_target_login_thread+0xadf/0x1050 [iscsi_target_mod]
> [  483.980346]  [<ffffffff8163b401>] ? __schedule+0x1f1/0x900
> [  483.986525]  [<ffffffffa09d0190>] ?
> iscsi_target_login_sess_out+0x250/0x250 [iscsi_target_mod]
> [  483.995816]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> [  484.001403]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> [  484.008608]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> [  484.014672]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> [  484.021896] INFO: task iscsi_trx:14795 blocked for more than 120 seconds.
> [  484.029349] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> disables this message.
> [  484.037849] iscsi_trx       D ffff887ee64f8000     0 14795      2 0x00000004
> [  484.045598]  ffff886e391bfbe0 0000000000000046 ffff887ed715c500
> ffff886e391bffd8
> [  484.053753]  ffff886e391bffd8 ffff886e391bffd8 ffff887ed715c500
> ffff887ee64f91d0
> [  484.061891]  ffff887ee64f91d8 7fffffffffffffff ffff887ed715c500
> ffff887ee64f8000
> [  484.070049] Call Trace:
> [  484.073174]  [<ffffffff8163bb39>] schedule+0x29/0x70
> [  484.078797]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
> [  484.085290]  [<ffffffffa0672125>] ? cm_alloc_msg+0x115/0x180 [ib_cm]
> [  484.092252]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
> [  484.098960]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
> [  484.105132]  [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
> [  484.112369]  [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
> [  484.119566]  [<ffffffffa09ddfbd>]
> iscsit_close_connection+0x15d/0x820 [iscsi_target_mod]
> [  484.128239]  [<ffffffff8163ca67>] ?
> wait_for_completion_interruptible+0x167/0x1d0
> [  484.136341]  [<ffffffffa09dcad0>] ?
> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
> [  484.145135]  [<ffffffffa09cc183>]
> iscsit_take_action_for_connection_exit+0x83/0x110 [iscsi_target_mod]
> [  484.155067]  [<ffffffffa09dccb7>]
> iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
> [  484.163700]  [<ffffffff81013588>] ? __switch_to+0xf8/0x4b0
> [  484.169774]  [<ffffffffa09dcad0>] ?
> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
> [  484.178530]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> [  484.183991]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> [  484.191106]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> [  484.197096]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
>
> I think there are two bugs here. Something in 4.9 iser (initiator) is
> causing a shutdown of the session when limited to 10 Gb. This second
> is in isert (target) where when a session isn't cleanly closed, it
> gets hung on cleaning up the session. It seems that bug #1 triggers
> bug #2 much easier than on Infiniband.
>
> I hope this is useful.
>
> ----------------
> Robert LeBlanc
> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>
>
> On Thu, Dec 29, 2016 at 4:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>> OK, I've drilled down a little more and
>>
>> timeout = action(timeout);
>>
>> in do_wait_for_common() in kernel/sched/completion.c is not returning.
>> I'll have to see if I can make more progress tomorrow.
>> ----------------
>> Robert LeBlanc
>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>
>>
>> On Thu, Dec 29, 2016 at 2:23 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>> I know most people are ignoring this thread by now, but I hope someone
>>> is still reading and can offer some ideas.
>>>
>>> It looks like ib_drain_qp_done() is not being called the first time
>>> that __ib_drain_sq() is called from iscsit_close_connection(). I tried
>>> to debug wait_for_completion() and friends, but they are called by too
>>> many things and I don't know how to filter out what I'm looking for.
>>> My next idea is to copy the completion functions here so that I can
>>> add debug to only that path. I feel like I'm inching closer to the
>>> problem, stumbling around in the dark.
>>>
>>> [Thu Dec 29 14:02:03 2016] Starting iscsit_close_connection.
>>> [Thu Dec 29 14:02:03 2016] isert_wait_conn calling ib_drain_qp.
>>> [Thu Dec 29 14:02:03 2016] ib_drain_qp calling ib_drain_sq.
>>> [Thu Dec 29 14:02:03 2016] ib_drain_sq calling __ib_drain_sq.
>>> [Thu Dec 29 14:02:03 2016] Setting up drain callback.
>>> [Thu Dec 29 14:02:03 2016] Starting init_completion.
>>> [Thu Dec 29 14:02:03 2016] Calling ib_modify_qp.
>>> [Thu Dec 29 14:02:03 2016] Calling ib_post_send.
>>> [Thu Dec 29 14:02:03 2016] Calling wait_for_completion.
>>> [Thu Dec 29 14:02:03 2016] &sdrain.done->done = 0.
>>>
>>> Gets "stuck" here...
>>>
>>> [Thu Dec 29 14:02:20 2016] iSCSI Login timeout on Network Portal 0.0.0.0:3260
>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp calling ib_drain_sq.
>>> [Thu Dec 29 14:02:37 2016] ib_drain_sq calling __ib_drain_sq.
>>> [Thu Dec 29 14:02:37 2016] Setting up drain callback.
>>> [Thu Dec 29 14:02:37 2016] Starting init_completion.
>>> [Thu Dec 29 14:02:37 2016] Calling ib_modify_qp.
>>> [Thu Dec 29 14:02:37 2016] Calling ib_post_send.
>>> [Thu Dec 29 14:02:37 2016] Calling wait_for_completion.
>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp_done going to call complete.
>>> [Thu Dec 29 14:02:38 2016] &sdrain.done->done = 1.
>>> [Thu Dec 29 14:02:38 2016] Returned from wait_for_completion.
>>> [Thu Dec 29 14:02:38 2016] ib_drain_qp_done going to call complete.
>>>
>>> Next time ib_drain_qp is called, ib_drain_qp_done gets called...
>>>
>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp calling ib_drain_sq.
>>> [Thu Dec 29 14:02:55 2016] ib_drain_sq calling __ib_drain_sq.
>>> [Thu Dec 29 14:02:55 2016] Setting up drain callback.
>>> [Thu Dec 29 14:02:55 2016] Starting init_completion.
>>> [Thu Dec 29 14:02:55 2016] Calling ib_modify_qp.
>>> [Thu Dec 29 14:02:55 2016] Calling ib_post_send.
>>> [Thu Dec 29 14:02:55 2016] Calling wait_for_completion.
>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
>>> [Thu Dec 29 14:02:55 2016] &sdrain.done->done = 1.
>>> [Thu Dec 29 14:02:55 2016] Returned from wait_for_completion.
>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
>>> ----------------
>>> Robert LeBlanc
>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>
>>>
>>> On Wed, Dec 28, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>> Good news! I found a 10 Gb switch laying around and put it in place of
>>>> the Linux router. I'm getting the same failure with the switch, so it
>>>> is not something funky with the Linux router and easier to replicate.
>>>> ----------------
>>>> Robert LeBlanc
>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>
>>>>
>>>> On Wed, Dec 28, 2016 at 1:39 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>> OK, here is some more info. This is a diagram of my current set up.
>>>>>
>>>>>                 +----------------+
>>>>>                 |  Linux Router  |
>>>>>                 |   ConnectX-3   |
>>>>>                 | port 1  port 2 |
>>>>>                 +----------------+
>>>>>                      /      \
>>>>> +---------------+   /        \   +---------------+
>>>>> |    Host 1     |  / A      A \  |    Host 2     |
>>>>> | ConnectX-4-LX | /            \ | ConnectX-4-LX |
>>>>> |        Port 1 |-              -| Port 1        |
>>>>> |        Port 2 |----------------| Port 2        |
>>>>> +---------------+        B       +---------------+
>>>>>
>>>>> The Linux router has the ConnectX-3 (not PRO) card in Ethernet mode
>>>>> and is using a breakout cable (port 1 only) to connect to the
>>>>> ConnectX-4-LX cards at 10 Gb as path 'A'. The second port of the
>>>>> ConnectX-4-LX cards are connected directly at 25 Gb as path 'B'.
>>>>>
>>>>> Running Iser and RoCE on path 'B' seems to run just fine.
>>>>>
>>>>> Running Iser and RoCE on path 'A' has issues when the Linux router is
>>>>> operating as a bridge or a router. Some small operations like mkfs
>>>>> seem to work just fine, but fio causes iser to want to log out and we
>>>>> get D state. I can run ib_send_bw 'all' tests through path 'A' and
>>>>> don't see a problem. It does seem to be load related, though. I have
>>>>> been trying to run
>>>>>
>>>>> echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K --size=1G
>>>>> --numjobs=40 --name=worker.matt --group_reporting
>>>>>
>>>>> If I reduce the number of jobs to 10 or less, it seems to work
>>>>> although I may see some of the debug messages I added in, it doesn't
>>>>> seem to completely hang and cause the logout lockup.
>>>>>
>>>>> Steps to reproduce:
>>>>> 1. 4.9 kernel
>>>>> 2. Bridge ports 1 & 2 on the Linux router
>>>>> 3. Configure port 1 on Host 1 & 2 on the same subnet
>>>>> 4. Create large ramdisk in targetcli and export from Host 1
>>>>> 5. Login from Host 2
>>>>> 6. Create EXT4 file system on imported disk
>>>>> 7. Mount and cd into mount
>>>>> 8. Run fio: echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K
>>>>> --size=1G --numjobs=40 --name=worker.matt --group_reporting
>>>>> 9. After some time, the fio process will report the file system is
>>>>> read only and the iscsi processes will be in D state on Host 1
>>>>>
>>>>> It does seem the problem is in iser and not specific to the generic RDMA stack.
>>>>>
>>>>> I'll keep digging and reporting back.
>>>>> ----------------
>>>>> Robert LeBlanc
>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>
>>>>>
>>>>> On Tue, Dec 27, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>> I realized that I did not set the default RoCE mode to v2 and the
>>>>>> client is on a different subnet, probably why I'm seeing the -110
>>>>>> error. Iser should not go into D state because of this and should
>>>>>> handle this gracefully, but may provide an easy way to replicate the
>>>>>> issue.
>>>>>> ----------------
>>>>>> Robert LeBlanc
>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>
>>>>>>
>>>>>> On Tue, Dec 27, 2016 at 1:22 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>> I looked at this code and it is quiet above my ability. I created this
>>>>>>> patch, but I don't know how to interrogate the queue to see how many
>>>>>>> items there are. If you can give me some more direction on what to
>>>>>>> try, I can keep fumbling around with this until someone smarter than
>>>>>>> me can figure it out. This is now a blocker for me so I'm going to
>>>>>>> beat my head on this until it is fixed.
>>>>>>>
>>>>>>> Thanks for being patient with me.
>>>>>>>
>>>>>>> diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
>>>>>>> index 8368764..9e5bd4b 100644
>>>>>>> --- a/drivers/infiniband/core/verbs.c
>>>>>>> +++ b/drivers/infiniband/core/verbs.c
>>>>>>> @@ -1954,22 +1954,27 @@ static void __ib_drain_sq(struct ib_qp *qp)
>>>>>>>                 return;
>>>>>>>         }
>>>>>>>
>>>>>>> +       printk("Setting up drain callback.");
>>>>>>>         swr.wr_cqe = &sdrain.cqe;
>>>>>>>         sdrain.cqe.done = ib_drain_qp_done;
>>>>>>> +       printk("Starting init_completion.");
>>>>>>>         init_completion(&sdrain.done);
>>>>>>>
>>>>>>> +       printk("Calling ib_modify_qp.");
>>>>>>>         ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
>>>>>>>         if (ret) {
>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
>>>>>>>                 return;
>>>>>>>         }
>>>>>>>
>>>>>>> +       printk("Calling ib_post_send.");
>>>>>>>         ret = ib_post_send(qp, &swr, &bad_swr);
>>>>>>>         if (ret) {
>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
>>>>>>>                 return;
>>>>>>>         }
>>>>>>>
>>>>>>> +       printk("Starting wait_for_completion.");
>>>>>>>         wait_for_completion(&sdrain.done);
>>>>>>>  }
>>>>>>>
>>>>>>> I get the same processes in D state (and same backtrace) and this is
>>>>>>> what shows up in dmesg:
>>>>>>>
>>>>>>> [  920.317401] isert: isert_rdma_accept: rdma_accept() failed with: -110
>>>>>>> [  920.325554] ------------[ cut here ]------------
>>>>>>> [  920.330188] WARNING: CPU: 11 PID: 705 at
>>>>>>> drivers/infiniband/core/verbs.c:303 ib_dealloc_pd+0x58/0xa0 [ib_core]
>>>>>>> [  920.340210] Modules linked in: target_core_user target_core_pscsi
>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
>>>>>>> iptable_filter rdma_ucm i
>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
>>>>>>> acpi_power_meter acpi_pad ip_table
>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
>>>>>>> mlx5_core igb mlx4_core
>>>>>>> [  920.412347]  ahci ptp drm libahci pps_core libata dca i2c_algo_bit
>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
>>>>>>> [  920.421744] CPU: 11 PID: 705 Comm: kworker/11:2 Not tainted 4.9.0+ #3
>>>>>>> [  920.428199] Hardware name: Supermicro SYS-6028TP-HTFR/X10DRT-PIBF,
>>>>>>> BIOS 1.1 08/03/2015
>>>>>>> [  920.436126] Workqueue: ib_cm cm_work_handler [ib_cm]
>>>>>>> [  920.441113]  ffffc90032a03a40 ffffffff8134d45f 0000000000000000
>>>>>>> 0000000000000000
>>>>>>> [  920.448583]  ffffc90032a03a80 ffffffff81083371 0000012fa04a1c4a
>>>>>>> ffff883f5e886e80
>>>>>>> [  920.456073]  ffff887f1eaa4400 ffff887f1eaa5800 ffffc90032a03b08
>>>>>>> 00000000ffffff92
>>>>>>> [  920.463535] Call Trace:
>>>>>>> [  920.465993]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
>>>>>>> [  920.471144]  [<ffffffff81083371>] __warn+0xd1/0xf0
>>>>>>> [  920.475941]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
>>>>>>> [  920.481790]  [<ffffffffa026cf58>] ib_dealloc_pd+0x58/0xa0 [ib_core]
>>>>>>> [  920.488072]  [<ffffffffa0695000>] isert_device_put+0x50/0xc0 [ib_isert]
>>>>>>> [  920.494693]  [<ffffffffa069838e>] isert_connect_request+0x68e/0xd40
>>>>>>> [ib_isert]
>>>>>>> [  920.501924]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0 [ib_isert]
>>>>>>> [  920.508725]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0 [rdma_cm]
>>>>>>> [  920.515521]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30 [rdma_cm]
>>>>>>> [  920.522227]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0 [rdma_cm]
>>>>>>> [  920.528851]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0 [ib_cm]
>>>>>>> [  920.535125]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70 [ib_cm]
>>>>>>> [  920.541485]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648 [ib_cm]
>>>>>>> [  920.548021]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
>>>>>>> [  920.553861]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
>>>>>>> [  920.559443]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
>>>>>>> [  920.565284]  [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>> [  920.570178]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
>>>>>>> [  920.576389]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>> [  920.582473] ---[ end trace 1f5a1831f9d2d964 ]---
>>>>>>> [  920.587907] ------------[ cut here ]------------
>>>>>>> [  920.593213] WARNING: CPU: 11 PID: 705 at
>>>>>>> drivers/infiniband/core/cq.c:189 ib_free_cq+0x97/0xc0 [ib_core]
>>>>>>> [  920.603383] Modules linked in: target_core_user target_core_pscsi
>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
>>>>>>> iptable_filter rdma_ucm i
>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
>>>>>>> acpi_power_meter acpi_pad ip_table
>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
>>>>>>> mlx5_core igb mlx4_core
>>>>>>> [  920.679694]  ahci ptp drm libahci pps_core libata dca i2c_algo_bit
>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
>>>>>>> [  920.690579] CPU: 11 PID: 705 Comm: kworker/11:2 Tainted: G        W
>>>>>>>       4.9.0+ #3
>>>>>>> [  920.699008] Hardware name: Supermicro SYS-6028TP-HTFR/X10DRT-PIBF,
>>>>>>> BIOS 1.1 08/03/2015
>>>>>>> [  920.707701] Workqueue: ib_cm cm_work_handler [ib_cm]
>>>>>>> [  920.713438]  ffffc90032a03a18 ffffffff8134d45f 0000000000000000
>>>>>>> 0000000000000000
>>>>>>> [  920.721648]  ffffc90032a03a58 ffffffff81083371 000000bd5e886e80
>>>>>>> ffff887f1eaa6800
>>>>>>> [  920.729850]  ffff883f5e886e20 ffff883f5e886e18 ffffc90032a03b08
>>>>>>> 00000000ffffff92
>>>>>>> [  920.738026] Call Trace:
>>>>>>> [  920.741188]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
>>>>>>> [  920.747027]  [<ffffffff81083371>] __warn+0xd1/0xf0
>>>>>>> [  920.752488]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
>>>>>>> [  920.758989]  [<ffffffffa026e037>] ib_free_cq+0x97/0xc0 [ib_core]
>>>>>>> [  920.765649]  [<ffffffffa0694f88>]
>>>>>>> isert_free_comps.isra.26+0x38/0x60 [ib_isert]
>>>>>>> [  920.773609]  [<ffffffffa069500d>] isert_device_put+0x5d/0xc0 [ib_isert]
>>>>>>> [  920.780868]  [<ffffffffa069838e>] isert_connect_request+0x68e/0xd40
>>>>>>> [ib_isert]
>>>>>>> [  920.788734]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0 [ib_isert]
>>>>>>> [  920.796157]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0 [rdma_cm]
>>>>>>> [  920.803586]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30 [rdma_cm]
>>>>>>> [  920.810916]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0 [rdma_cm]
>>>>>>> [  920.818167]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0 [ib_cm]
>>>>>>> [  920.825063]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70 [ib_cm]
>>>>>>> [  920.832051]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648 [ib_cm]
>>>>>>> [  920.839208]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
>>>>>>> [  920.845669]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
>>>>>>> [  920.851880]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
>>>>>>> [  920.858352]  [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>> [  920.863857]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
>>>>>>> [  920.869975]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>> [  920.876006] ---[ end trace 1f5a1831f9d2d965 ]---
>>>>>>> [  920.884335] isert: isert_cma_handler: failed handle connect request -110
>>>>>>> [ 1639.592451] Setting up drain callback.
>>>>>>> [ 1639.596073] Starting init_completion.
>>>>>>> [ 1639.600683] Calling ib_modify_qp.
>>>>>>> [ 1639.602616] Calling ib_post_send.
>>>>>>> [ 1639.606550] Starting wait_for_completion.
>>>>>>> [ 1656.976015] iSCSI Login timeout on Network Portal 0.0.0.0:3260
>>>>>>> [ 1674.254027] Setting up drain callback.
>>>>>>> [ 1674.257634] Starting init_completion.
>>>>>>> [ 1674.262107] Calling ib_modify_qp.
>>>>>>> [ 1674.264011] Calling ib_post_send.
>>>>>>> [ 1674.267969] Starting wait_for_completion.
>>>>>>> [ 1691.583888] Setting up drain callback.
>>>>>>> [ 1691.588490] Starting init_completion.
>>>>>>> [ 1691.590677] Calling ib_modify_qp.
>>>>>>> [ 1691.594766] Calling ib_post_send.
>>>>>>> [ 1691.596607] Starting wait_for_completion.
>>>>>>> [ 1708.913356] Setting up drain callback.
>>>>>>> [ 1708.915658] Starting init_completion.
>>>>>>> [ 1708.920152] Calling ib_modify_qp.
>>>>>>> [ 1708.922041] Calling ib_post_send.
>>>>>>> [ 1708.926048] Starting wait_for_completion.
>>>>>>> [ 1726.244365] Setting up drain callback.
>>>>>>> [ 1726.248973] Starting init_completion.
>>>>>>> [ 1726.251165] Calling ib_modify_qp.
>>>>>>> [ 1726.255189] Calling ib_post_send.
>>>>>>> [ 1726.257031] Starting wait_for_completion.
>>>>>>> [ 1743.574751] Setting up drain callback.
>>>>>>> [ 1743.577044] Starting init_completion.
>>>>>>> [ 1743.581496] Calling ib_modify_qp.
>>>>>>> [ 1743.583404] Calling ib_post_send.
>>>>>>> [ 1743.587346] Starting wait_for_completion.
>>>>>>> [ 1760.904470] Setting up drain callback.
>>>>>>> [ 1760.908991] Starting init_completion.
>>>>>>> [ 1760.911206] Calling ib_modify_qp.
>>>>>>> [ 1760.915214] Calling ib_post_send.
>>>>>>> [ 1760.917062] Starting wait_for_completion.
>>>>>>> [ 1778.230821] Setting up drain callback.
>>>>>>> [ 1778.233116] Starting init_completion.
>>>>>>> [ 1778.237510] Calling ib_modify_qp.
>>>>>>> [ 1778.239413] Calling ib_post_send.
>>>>>>> .... [keeps repeating]
>>>>>>> ----------------
>>>>>>> Robert LeBlanc
>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>
>>>>>>>
>>>>>>> On Thu, Dec 22, 2016 at 12:15 PM, Doug Ledford <dledford@redhat.com> wrote:
>>>>>>>> On 12/21/2016 6:39 PM, Robert LeBlanc wrote:
>>>>>>>>> I hit a new backtrace today, hopefully it adds something.
>>>>>>>>>
>>>>>>>>> # cat /proc/19659/stack
>>>>>>>>> [<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
>>>>>>>>> [<ffffffff81521c62>] iscsi_check_for_session_reinstatement+0x1e2/0x270
>>>>>>>>> [<ffffffff81524660>] iscsi_target_check_for_existing_instances+0x30/0x40
>>>>>>>>> [<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
>>>>>>>>> [<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
>>>>>>>>> [<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
>>>>>>>>> [<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>
>>>>>>>>> # cat /proc/21342/stack
>>>>>>>>> [<ffffffffa0292b10>] __ib_drain_sq+0x190/0x1c0 [ib_core]
>>>>>>>>> [<ffffffffa0292b65>] ib_drain_sq+0x25/0x30 [ib_core]
>>>>>>>>> [<ffffffffa0292d72>] ib_drain_qp+0x12/0x30 [ib_core]
>>>>>>>>> [<ffffffffa062c5ff>] isert_wait_conn+0x5f/0x2d0 [ib_isert]
>>>>>>>>> [<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
>>>>>>>>> [<ffffffff8151f10b>] iscsit_take_action_for_connection_exit+0x7b/0xf0
>>>>>>>>> [<ffffffff81530265>] iscsi_target_rx_thread+0x95/0xa0
>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>
>>>>>>>>> # ps aux | grep iscsi | grep D
>>>>>>>>> root     19659  0.0  0.0      0     0 ?        D    16:12   0:00 [iscsi_np]
>>>>>>>>> root     21342  0.0  0.0      0     0 ?        D    16:29   0:00 [iscsi_trx]
>>>>>>>>> ----------------
>>>>>>>>> Robert LeBlanc
>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>
>>>>>>>> That looks suspiciously like the __ib_drain_sq is stuck forever waiting
>>>>>>>> on a completion that never comes.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Thu, Dec 15, 2016 at 1:38 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>> Nicholas,
>>>>>>>>>>
>>>>>>>>>> I've found that the kernels I used were not able to be inspected using
>>>>>>>>>> crash and I could not build the debug info for them. So I built a new
>>>>>>>>>> 4.9 kernel and verified that I could inspect the crash. It is located
>>>>>>>>>> at [1].
>>>>>>>>>>
>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash2.tar.xz
>>>>>>>>>> ----------------
>>>>>>>>>> Robert LeBlanc
>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Mon, Dec 12, 2016 at 4:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>>> Nicholas,
>>>>>>>>>>>
>>>>>>>>>>> After lots of set backs and having to give up trying to get kernel
>>>>>>>>>>> dumps on our "production" systems, I've been able to work out the
>>>>>>>>>>> issues we had with kdump and replicate the issue on my dev boxes. I
>>>>>>>>>>> have dumps from 4.4.30 and 4.9-rc8 (makedumpfile would not dump, so it
>>>>>>>>>>> is a straight copy of /proc/vmcore from the crash kernel). In each
>>>>>>>>>>> crash directory, I put a details.txt file that has the process IDs
>>>>>>>>>>> that were having problems and a brief description of the set-up at the
>>>>>>>>>>> time. This was mostly replicated by starting fio and pulling the
>>>>>>>>>>> Infiniband cable until fio gave up. This hardware also has Mellanox
>>>>>>>>>>> ConnectX4-LX cards and I also replicated the issue over RoCE using 4.9
>>>>>>>>>>> since it has the drivers in-box. Please let me know if you need more
>>>>>>>>>>> info, I can test much faster now. The cores/kernels/modules are
>>>>>>>>>>> located at [1].
>>>>>>>>>>>
>>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash.tar.xz
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Robert
>>>>>>>>>>> ----------------
>>>>>>>>>>> Robert LeBlanc
>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Fri, Nov 4, 2016 at 3:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>>>> We hit this yesterday, this time it was on the tx thread (the other
>>>>>>>>>>>> ones before seem to be on the rx thread). We weren't able to get a
>>>>>>>>>>>> kernel dump on this. We'll try to get one next time.
>>>>>>>>>>>>
>>>>>>>>>>>> # ps axuw | grep "D.*iscs[i]"
>>>>>>>>>>>> root     12383  0.0  0.0      0     0 ?        D    Nov03   0:04 [iscsi_np]
>>>>>>>>>>>> root     23016  0.0  0.0      0     0 ?        D    Nov03   0:00 [iscsi_ttx]
>>>>>>>>>>>> root     23018  0.0  0.0      0     0 ?        D    Nov03   0:00 [iscsi_ttx]
>>>>>>>>>>>> # cat /proc/12383/stack
>>>>>>>>>>>> [<ffffffff814f24af>] iscsit_stop_session+0x19f/0x1d0
>>>>>>>>>>>> [<ffffffff814e3c66>] iscsi_check_for_session_reinstatement+0x1e6/0x270
>>>>>>>>>>>> [<ffffffff814e6620>] iscsi_target_check_for_existing_instances+0x30/0x40
>>>>>>>>>>>> [<ffffffff814e6770>] iscsi_target_do_login+0x140/0x640
>>>>>>>>>>>> [<ffffffff814e7b0c>] iscsi_target_start_negotiation+0x1c/0xb0
>>>>>>>>>>>> [<ffffffff814e585b>] iscsi_target_login_thread+0xa9b/0xfc0
>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>> # cat /proc/23016/stack
>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
>>>>>>>>>>>> [<ffffffff814e110f>] iscsit_take_action_for_connection_exit+0x7f/0x100
>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>> # cat /proc/23018/stack
>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
>>>>>>>>>>>> [<ffffffff814e110f>] iscsit_take_action_for_connection_exit+0x7f/0x100
>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>>
>>>>>>>>>>>> From dmesg:
>>>>>>>>>>>> [  394.476332] INFO: rcu_sched self-detected stall on CPU
>>>>>>>>>>>> [  394.476334]  20-...: (23976 ticks this GP)
>>>>>>>>>>>> idle=edd/140000000000001/0 softirq=292/292 fqs=18788
>>>>>>>>>>>> [  394.476336]   (t=24003 jiffies g=3146 c=3145 q=0)
>>>>>>>>>>>> [  394.476337] Task dump for CPU 20:
>>>>>>>>>>>> [  394.476338] kworker/u68:2   R  running task        0 12906      2 0x00000008
>>>>>>>>>>>> [  394.476345] Workqueue: isert_comp_wq isert_cq_work [ib_isert]
>>>>>>>>>>>> [  394.476346]  ffff883f2fe38000 00000000f805705e ffff883f7fd03da8
>>>>>>>>>>>> ffffffff810ac8ff
>>>>>>>>>>>> [  394.476347]  0000000000000014 ffffffff81adb680 ffff883f7fd03dc0
>>>>>>>>>>>> ffffffff810af239
>>>>>>>>>>>> [  394.476348]  0000000000000015 ffff883f7fd03df0 ffffffff810e1cd0
>>>>>>>>>>>> ffff883f7fd17b80
>>>>>>>>>>>> [  394.476348] Call Trace:
>>>>>>>>>>>> [  394.476354]  <IRQ>  [<ffffffff810ac8ff>] sched_show_task+0xaf/0x110
>>>>>>>>>>>> [  394.476355]  [<ffffffff810af239>] dump_cpu_task+0x39/0x40
>>>>>>>>>>>> [  394.476357]  [<ffffffff810e1cd0>] rcu_dump_cpu_stacks+0x80/0xb0
>>>>>>>>>>>> [  394.476359]  [<ffffffff810e6100>] rcu_check_callbacks+0x540/0x820
>>>>>>>>>>>> [  394.476360]  [<ffffffff810afe11>] ? account_system_time+0x81/0x110
>>>>>>>>>>>> [  394.476363]  [<ffffffff810faa60>] ? tick_sched_do_timer+0x50/0x50
>>>>>>>>>>>> [  394.476364]  [<ffffffff810eb599>] update_process_times+0x39/0x60
>>>>>>>>>>>> [  394.476365]  [<ffffffff810fa815>] tick_sched_handle.isra.17+0x25/0x60
>>>>>>>>>>>> [  394.476366]  [<ffffffff810faa9d>] tick_sched_timer+0x3d/0x70
>>>>>>>>>>>> [  394.476368]  [<ffffffff810ec182>] __hrtimer_run_queues+0x102/0x290
>>>>>>>>>>>> [  394.476369]  [<ffffffff810ec668>] hrtimer_interrupt+0xa8/0x1a0
>>>>>>>>>>>> [  394.476372]  [<ffffffff81052c65>] local_apic_timer_interrupt+0x35/0x60
>>>>>>>>>>>> [  394.476374]  [<ffffffff8172423d>] smp_apic_timer_interrupt+0x3d/0x50
>>>>>>>>>>>> [  394.476376]  [<ffffffff817224f7>] apic_timer_interrupt+0x87/0x90
>>>>>>>>>>>> [  394.476379]  <EOI>  [<ffffffff810d71be>] ? console_unlock+0x41e/0x4e0
>>>>>>>>>>>> [  394.476380]  [<ffffffff810d757c>] vprintk_emit+0x2fc/0x500
>>>>>>>>>>>> [  394.476382]  [<ffffffff810d78ff>] vprintk_default+0x1f/0x30
>>>>>>>>>>>> [  394.476384]  [<ffffffff81174dde>] printk+0x5d/0x74
>>>>>>>>>>>> [  394.476388]  [<ffffffff814bce21>] transport_lookup_cmd_lun+0x1d1/0x200
>>>>>>>>>>>> [  394.476390]  [<ffffffff814ee8c0>] iscsit_setup_scsi_cmd+0x230/0x540
>>>>>>>>>>>> [  394.476392]  [<ffffffffa058dbf3>] isert_rx_do_work+0x3f3/0x7f0 [ib_isert]
>>>>>>>>>>>> [  394.476394]  [<ffffffffa058e174>] isert_cq_work+0x184/0x770 [ib_isert]
>>>>>>>>>>>> [  394.476396]  [<ffffffff8109740f>] process_one_work+0x14f/0x400
>>>>>>>>>>>> [  394.476397]  [<ffffffff81097c84>] worker_thread+0x114/0x470
>>>>>>>>>>>> [  394.476398]  [<ffffffff8171d32a>] ? __schedule+0x34a/0x7f0
>>>>>>>>>>>> [  394.476399]  [<ffffffff81097b70>] ? rescuer_thread+0x310/0x310
>>>>>>>>>>>> [  394.476400]  [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>> [  394.476402]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
>>>>>>>>>>>> [  394.476403]  [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>> [  394.476404]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
>>>>>>>>>>>> [  405.716632] Unexpected ret: -104 send data 360
>>>>>>>>>>>> [  405.721711] tx_data returned -32, expecting 360.
>>>>>>>>>>>> ----------------
>>>>>>>>>>>> Robert LeBlanc
>>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>
>>>>>>>> When you combine this trace with the newest one, it really makes me
>>>>>>>> thing there is something of a bad interaction between the new drain cq
>>>>>>>> API and the iser/isert implementation to use said API.  Sagi, Christoph?
>>>>>>>>
>>>>>>>> --
>>>>>>>> Doug Ledford <dledford@redhat.com>
>>>>>>>>     GPG Key ID: B826A3330E572FDD
>>>>>>>>     Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD
>>>>>>>>
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Comments

Robert LeBlanc Jan. 4, 2017, 12:11 a.m. UTC | #1
With the last patch it is getting hung up on wait_for_completion in
target_wait_for_sess_cmds. I don't know what t_state or fabric state
mean. To me it looks like a queue is not being emptied, but it would
help if someone confirmed this and has some pointers on how to
properly flush them when the communication is interrupted.

[  222.989134] Starting iscsit_close_connection.
[  222.993555] Calling flush_workqueue.
[  222.997703] Returned from flush_workqueue.
[  223.005802] isert_wait_conn calling ib_close_qp/ib_drain_qp.
[  223.011892] isert_wait_conn finished ib_close_qp/ib_drain_qp.
[  223.018063] isert_wait_conn calling isert_put_unsol_pending_cmds.
[  223.024574] isert_wait_conn returned from
isert_put_unsol_pending_cmds.
[  223.031582] isert_wait_conn calling isert_wait4cmds.
[  223.036942] isert_wait4cmds calling
target_sess_cmd_list_set_waiting.
[  223.043789] isert_wait4cmds returned from
target_sess_cmd_list_set_waiting.
[  223.051135] isert_wait4cmds calling target_wait_for_sess_cmds.
[  223.057362] Waiting for se_cmd: ffff887ebf88bd00 t_state: 6, fabric
state: 29
[  223.064893] target_wait_for_sess_cmds calling
spin_unlock_irqrestore.
[  223.071748] target_wait_for_sess_cmds calling wait_for_completion.
[  224.997636] Calling wait_for_common.
[  225.001936] Starting __wait_for_common.
[  225.006226] Calling do_wait_for_common.

Thanks
----------------
Robert LeBlanc
PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1


On Tue, Jan 3, 2017 at 1:07 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
> With this patch I'm not seeing the __ib_drain_sq backtraces, but I'm
> still seeing the previous backtraces.
>
> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
> b/drivers/infiniband/ulp/isert/ib_isert.c
> index 6dd43f6..1e53502 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.c
> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> @@ -2595,7 +2595,7 @@ static void isert_wait_conn(struct iscsi_conn *conn)
>        isert_conn_terminate(isert_conn);
>        mutex_unlock(&isert_conn->mutex);
>
> -       ib_drain_qp(isert_conn->qp);
> +       ib_close_qp(isert_conn->qp);
>        isert_put_unsol_pending_cmds(conn);
>        isert_wait4cmds(conn);
>        isert_wait4logout(isert_conn);
>
> I was thinking that if the connection was brought down uncleanly then
> there may be messages(??) it the send queue that would never be
> consumed by the application, so it would never drain and would have to
> be forcibly emptied. Maybe there is something stuck in the command
> queue as well?
>
> [(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
> root     15426  0.0  0.0      0     0 ?        D    12:48   0:00 [iscsi_np]
> root     15429  0.0  0.0      0     0 ?        D    12:48   0:00 [iscsi_ttx]
> root     16077  0.0  0.0 112656  2216 pts/0    S+   12:55   0:00 grep
> --color=auto  D
> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15426/stack
> [<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
> [<ffffffff81521c62>] iscsi_check_for_session_reinstatement+0x1e2/0x270
> [<ffffffff81524660>] iscsi_target_check_for_existing_instances+0x30/0x40
> [<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
> [<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
> [<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
> [<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
> [<ffffffff810a3059>] kthread+0xd9/0xf0
> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> [<ffffffffffffffff>] 0xffffffffffffffff
> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15429/stack
> [<ffffffff8150c689>] target_wait_for_sess_cmds+0x49/0x190
> [<ffffffffa0705744>] isert_wait_conn+0x1a4/0x2d0 [ib_isert]
> [<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
> [<ffffffff8151f10b>] iscsit_take_action_for_connection_exit+0x7b/0xf0
> [<ffffffff81530150>] iscsi_target_tx_thread+0x150/0x1d0
> [<ffffffff810a3059>] kthread+0xd9/0xf0
> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> [<ffffffffffffffff>] 0xffffffffffffffff
> ----------------
> Robert LeBlanc
> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>
>
> On Fri, Dec 30, 2016 at 4:07 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>> I decided to try something completely different... Running the stock
>> CentOS 3.10 kernel and OFED 3.4 on both hosts, I'm not seeing the hung
>> processes and the tests complete successfully. The same seems to be
>> true for the target on 4.9 and the initiator on 3.10.
>>
>> However, with the target on 3.10 and the initiator on 4.9, I get this
>> on the target:
>>
>> [(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
>> root     14791  0.0  0.0      0     0 ?        D    15:08   0:00 [iscsi_np]
>> root     14795  0.0  0.0      0     0 ?        D    15:08   0:00 [iscsi_trx]
>> root     14852  0.0  0.0 112648   976 pts/0    S+   15:11   0:00 grep
>> --color=auto  D
>> [(support-1.0) root@prv-0-13-roberttest ~]# uname -a
>> Linux prv-0-13-roberttest.betterservers.com 3.10.0-327.36.3.el7.x86_64
>> #1 SMP Mon Oct 24 16:09:20 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
>> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14791/stack
>> [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0 [iscsi_target_mod]
>> [<ffffffffa09ceefa>] iscsi_check_for_session_reinstatement+0x1ea/0x280
>> [iscsi_target_mod]
>> [<ffffffffa09d19f5>]
>> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
>> [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670 [iscsi_target_mod]
>> [<ffffffffa09d2f4c>] iscsi_target_start_negotiation+0x1c/0xb0 [iscsi_target_mod]
>> [<ffffffffa09d0c6f>] iscsi_target_login_thread+0xadf/0x1050 [iscsi_target_mod]
>> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
>> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
>> [<ffffffffffffffff>] 0xffffffffffffffff
>> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14795/stack
>> [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
>> [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
>> [<ffffffffa09ddfbd>] iscsit_close_connection+0x15d/0x820 [iscsi_target_mod]
>> [<ffffffffa09cc183>] iscsit_take_action_for_connection_exit+0x83/0x110
>> [iscsi_target_mod]
>> [<ffffffffa09dccb7>] iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
>> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
>> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
>> [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> [  345.970157] iSCSI Login timeout on Network Portal 0.0.0.0:3260
>> [  483.850714] INFO: task iscsi_np:14791 blocked for more than 120 seconds.
>> [  483.857467] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
>> disables this message.
>> [  483.865326] iscsi_np        D 0000000000000000     0 14791      2 0x00000004
>> [  483.872460]  ffff886e3b117be0 0000000000000046 ffff887ede579700
>> ffff886e3b117fd8
>> [  483.879983]  ffff886e3b117fd8 ffff886e3b117fd8 ffff887ede579700
>> ffff883ef7898160
>> [  483.887500]  ffff883ef7898168 7fffffffffffffff ffff887ede579700
>> 0000000000000000
>> [  483.895025] Call Trace:
>> [  483.897505]  [<ffffffff8163bb39>] schedule+0x29/0x70
>> [  483.902496]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
>> [  483.908355]  [<ffffffff812fc60b>] ? simple_strtoull+0x3b/0x70
>> [  483.914128]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
>> [  483.920253]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
>> [  483.925847]  [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0
>> [iscsi_target_mod]
>> [  483.933612]  [<ffffffffa09ceefa>]
>> iscsi_check_for_session_reinstatement+0x1ea/0x280 [iscsi_target_mod]
>> [  483.942944]  [<ffffffffa09d19f5>]
>> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
>> [  483.953304]  [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670
>> [iscsi_target_mod]
>> [  483.961988]  [<ffffffffa09d2f4c>]
>> iscsi_target_start_negotiation+0x1c/0xb0 [iscsi_target_mod]
>> [  483.971278]  [<ffffffffa09d0c6f>]
>> iscsi_target_login_thread+0xadf/0x1050 [iscsi_target_mod]
>> [  483.980346]  [<ffffffff8163b401>] ? __schedule+0x1f1/0x900
>> [  483.986525]  [<ffffffffa09d0190>] ?
>> iscsi_target_login_sess_out+0x250/0x250 [iscsi_target_mod]
>> [  483.995816]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
>> [  484.001403]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
>> [  484.008608]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
>> [  484.014672]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
>> [  484.021896] INFO: task iscsi_trx:14795 blocked for more than 120 seconds.
>> [  484.029349] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
>> disables this message.
>> [  484.037849] iscsi_trx       D ffff887ee64f8000     0 14795      2 0x00000004
>> [  484.045598]  ffff886e391bfbe0 0000000000000046 ffff887ed715c500
>> ffff886e391bffd8
>> [  484.053753]  ffff886e391bffd8 ffff886e391bffd8 ffff887ed715c500
>> ffff887ee64f91d0
>> [  484.061891]  ffff887ee64f91d8 7fffffffffffffff ffff887ed715c500
>> ffff887ee64f8000
>> [  484.070049] Call Trace:
>> [  484.073174]  [<ffffffff8163bb39>] schedule+0x29/0x70
>> [  484.078797]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
>> [  484.085290]  [<ffffffffa0672125>] ? cm_alloc_msg+0x115/0x180 [ib_cm]
>> [  484.092252]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
>> [  484.098960]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
>> [  484.105132]  [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
>> [  484.112369]  [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
>> [  484.119566]  [<ffffffffa09ddfbd>]
>> iscsit_close_connection+0x15d/0x820 [iscsi_target_mod]
>> [  484.128239]  [<ffffffff8163ca67>] ?
>> wait_for_completion_interruptible+0x167/0x1d0
>> [  484.136341]  [<ffffffffa09dcad0>] ?
>> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
>> [  484.145135]  [<ffffffffa09cc183>]
>> iscsit_take_action_for_connection_exit+0x83/0x110 [iscsi_target_mod]
>> [  484.155067]  [<ffffffffa09dccb7>]
>> iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
>> [  484.163700]  [<ffffffff81013588>] ? __switch_to+0xf8/0x4b0
>> [  484.169774]  [<ffffffffa09dcad0>] ?
>> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
>> [  484.178530]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
>> [  484.183991]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
>> [  484.191106]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
>> [  484.197096]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
>>
>> I think there are two bugs here. Something in 4.9 iser (initiator) is
>> causing a shutdown of the session when limited to 10 Gb. This second
>> is in isert (target) where when a session isn't cleanly closed, it
>> gets hung on cleaning up the session. It seems that bug #1 triggers
>> bug #2 much easier than on Infiniband.
>>
>> I hope this is useful.
>>
>> ----------------
>> Robert LeBlanc
>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>
>>
>> On Thu, Dec 29, 2016 at 4:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>> OK, I've drilled down a little more and
>>>
>>> timeout = action(timeout);
>>>
>>> in do_wait_for_common() in kernel/sched/completion.c is not returning.
>>> I'll have to see if I can make more progress tomorrow.
>>> ----------------
>>> Robert LeBlanc
>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>
>>>
>>> On Thu, Dec 29, 2016 at 2:23 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>> I know most people are ignoring this thread by now, but I hope someone
>>>> is still reading and can offer some ideas.
>>>>
>>>> It looks like ib_drain_qp_done() is not being called the first time
>>>> that __ib_drain_sq() is called from iscsit_close_connection(). I tried
>>>> to debug wait_for_completion() and friends, but they are called by too
>>>> many things and I don't know how to filter out what I'm looking for.
>>>> My next idea is to copy the completion functions here so that I can
>>>> add debug to only that path. I feel like I'm inching closer to the
>>>> problem, stumbling around in the dark.
>>>>
>>>> [Thu Dec 29 14:02:03 2016] Starting iscsit_close_connection.
>>>> [Thu Dec 29 14:02:03 2016] isert_wait_conn calling ib_drain_qp.
>>>> [Thu Dec 29 14:02:03 2016] ib_drain_qp calling ib_drain_sq.
>>>> [Thu Dec 29 14:02:03 2016] ib_drain_sq calling __ib_drain_sq.
>>>> [Thu Dec 29 14:02:03 2016] Setting up drain callback.
>>>> [Thu Dec 29 14:02:03 2016] Starting init_completion.
>>>> [Thu Dec 29 14:02:03 2016] Calling ib_modify_qp.
>>>> [Thu Dec 29 14:02:03 2016] Calling ib_post_send.
>>>> [Thu Dec 29 14:02:03 2016] Calling wait_for_completion.
>>>> [Thu Dec 29 14:02:03 2016] &sdrain.done->done = 0.
>>>>
>>>> Gets "stuck" here...
>>>>
>>>> [Thu Dec 29 14:02:20 2016] iSCSI Login timeout on Network Portal 0.0.0.0:3260
>>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp calling ib_drain_sq.
>>>> [Thu Dec 29 14:02:37 2016] ib_drain_sq calling __ib_drain_sq.
>>>> [Thu Dec 29 14:02:37 2016] Setting up drain callback.
>>>> [Thu Dec 29 14:02:37 2016] Starting init_completion.
>>>> [Thu Dec 29 14:02:37 2016] Calling ib_modify_qp.
>>>> [Thu Dec 29 14:02:37 2016] Calling ib_post_send.
>>>> [Thu Dec 29 14:02:37 2016] Calling wait_for_completion.
>>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp_done going to call complete.
>>>> [Thu Dec 29 14:02:38 2016] &sdrain.done->done = 1.
>>>> [Thu Dec 29 14:02:38 2016] Returned from wait_for_completion.
>>>> [Thu Dec 29 14:02:38 2016] ib_drain_qp_done going to call complete.
>>>>
>>>> Next time ib_drain_qp is called, ib_drain_qp_done gets called...
>>>>
>>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp calling ib_drain_sq.
>>>> [Thu Dec 29 14:02:55 2016] ib_drain_sq calling __ib_drain_sq.
>>>> [Thu Dec 29 14:02:55 2016] Setting up drain callback.
>>>> [Thu Dec 29 14:02:55 2016] Starting init_completion.
>>>> [Thu Dec 29 14:02:55 2016] Calling ib_modify_qp.
>>>> [Thu Dec 29 14:02:55 2016] Calling ib_post_send.
>>>> [Thu Dec 29 14:02:55 2016] Calling wait_for_completion.
>>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
>>>> [Thu Dec 29 14:02:55 2016] &sdrain.done->done = 1.
>>>> [Thu Dec 29 14:02:55 2016] Returned from wait_for_completion.
>>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
>>>> ----------------
>>>> Robert LeBlanc
>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>
>>>>
>>>> On Wed, Dec 28, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>> Good news! I found a 10 Gb switch laying around and put it in place of
>>>>> the Linux router. I'm getting the same failure with the switch, so it
>>>>> is not something funky with the Linux router and easier to replicate.
>>>>> ----------------
>>>>> Robert LeBlanc
>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>
>>>>>
>>>>> On Wed, Dec 28, 2016 at 1:39 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>> OK, here is some more info. This is a diagram of my current set up.
>>>>>>
>>>>>>                 +----------------+
>>>>>>                 |  Linux Router  |
>>>>>>                 |   ConnectX-3   |
>>>>>>                 | port 1  port 2 |
>>>>>>                 +----------------+
>>>>>>                      /      \
>>>>>> +---------------+   /        \   +---------------+
>>>>>> |    Host 1     |  / A      A \  |    Host 2     |
>>>>>> | ConnectX-4-LX | /            \ | ConnectX-4-LX |
>>>>>> |        Port 1 |-              -| Port 1        |
>>>>>> |        Port 2 |----------------| Port 2        |
>>>>>> +---------------+        B       +---------------+
>>>>>>
>>>>>> The Linux router has the ConnectX-3 (not PRO) card in Ethernet mode
>>>>>> and is using a breakout cable (port 1 only) to connect to the
>>>>>> ConnectX-4-LX cards at 10 Gb as path 'A'. The second port of the
>>>>>> ConnectX-4-LX cards are connected directly at 25 Gb as path 'B'.
>>>>>>
>>>>>> Running Iser and RoCE on path 'B' seems to run just fine.
>>>>>>
>>>>>> Running Iser and RoCE on path 'A' has issues when the Linux router is
>>>>>> operating as a bridge or a router. Some small operations like mkfs
>>>>>> seem to work just fine, but fio causes iser to want to log out and we
>>>>>> get D state. I can run ib_send_bw 'all' tests through path 'A' and
>>>>>> don't see a problem. It does seem to be load related, though. I have
>>>>>> been trying to run
>>>>>>
>>>>>> echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K --size=1G
>>>>>> --numjobs=40 --name=worker.matt --group_reporting
>>>>>>
>>>>>> If I reduce the number of jobs to 10 or less, it seems to work
>>>>>> although I may see some of the debug messages I added in, it doesn't
>>>>>> seem to completely hang and cause the logout lockup.
>>>>>>
>>>>>> Steps to reproduce:
>>>>>> 1. 4.9 kernel
>>>>>> 2. Bridge ports 1 & 2 on the Linux router
>>>>>> 3. Configure port 1 on Host 1 & 2 on the same subnet
>>>>>> 4. Create large ramdisk in targetcli and export from Host 1
>>>>>> 5. Login from Host 2
>>>>>> 6. Create EXT4 file system on imported disk
>>>>>> 7. Mount and cd into mount
>>>>>> 8. Run fio: echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K
>>>>>> --size=1G --numjobs=40 --name=worker.matt --group_reporting
>>>>>> 9. After some time, the fio process will report the file system is
>>>>>> read only and the iscsi processes will be in D state on Host 1
>>>>>>
>>>>>> It does seem the problem is in iser and not specific to the generic RDMA stack.
>>>>>>
>>>>>> I'll keep digging and reporting back.
>>>>>> ----------------
>>>>>> Robert LeBlanc
>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>
>>>>>>
>>>>>> On Tue, Dec 27, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>> I realized that I did not set the default RoCE mode to v2 and the
>>>>>>> client is on a different subnet, probably why I'm seeing the -110
>>>>>>> error. Iser should not go into D state because of this and should
>>>>>>> handle this gracefully, but may provide an easy way to replicate the
>>>>>>> issue.
>>>>>>> ----------------
>>>>>>> Robert LeBlanc
>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Dec 27, 2016 at 1:22 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>> I looked at this code and it is quiet above my ability. I created this
>>>>>>>> patch, but I don't know how to interrogate the queue to see how many
>>>>>>>> items there are. If you can give me some more direction on what to
>>>>>>>> try, I can keep fumbling around with this until someone smarter than
>>>>>>>> me can figure it out. This is now a blocker for me so I'm going to
>>>>>>>> beat my head on this until it is fixed.
>>>>>>>>
>>>>>>>> Thanks for being patient with me.
>>>>>>>>
>>>>>>>> diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
>>>>>>>> index 8368764..9e5bd4b 100644
>>>>>>>> --- a/drivers/infiniband/core/verbs.c
>>>>>>>> +++ b/drivers/infiniband/core/verbs.c
>>>>>>>> @@ -1954,22 +1954,27 @@ static void __ib_drain_sq(struct ib_qp *qp)
>>>>>>>>                 return;
>>>>>>>>         }
>>>>>>>>
>>>>>>>> +       printk("Setting up drain callback.");
>>>>>>>>         swr.wr_cqe = &sdrain.cqe;
>>>>>>>>         sdrain.cqe.done = ib_drain_qp_done;
>>>>>>>> +       printk("Starting init_completion.");
>>>>>>>>         init_completion(&sdrain.done);
>>>>>>>>
>>>>>>>> +       printk("Calling ib_modify_qp.");
>>>>>>>>         ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
>>>>>>>>         if (ret) {
>>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
>>>>>>>>                 return;
>>>>>>>>         }
>>>>>>>>
>>>>>>>> +       printk("Calling ib_post_send.");
>>>>>>>>         ret = ib_post_send(qp, &swr, &bad_swr);
>>>>>>>>         if (ret) {
>>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n", ret);
>>>>>>>>                 return;
>>>>>>>>         }
>>>>>>>>
>>>>>>>> +       printk("Starting wait_for_completion.");
>>>>>>>>         wait_for_completion(&sdrain.done);
>>>>>>>>  }
>>>>>>>>
>>>>>>>> I get the same processes in D state (and same backtrace) and this is
>>>>>>>> what shows up in dmesg:
>>>>>>>>
>>>>>>>> [  920.317401] isert: isert_rdma_accept: rdma_accept() failed with: -110
>>>>>>>> [  920.325554] ------------[ cut here ]------------
>>>>>>>> [  920.330188] WARNING: CPU: 11 PID: 705 at
>>>>>>>> drivers/infiniband/core/verbs.c:303 ib_dealloc_pd+0x58/0xa0 [ib_core]
>>>>>>>> [  920.340210] Modules linked in: target_core_user target_core_pscsi
>>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
>>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
>>>>>>>> iptable_filter rdma_ucm i
>>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
>>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
>>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
>>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
>>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
>>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
>>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
>>>>>>>> acpi_power_meter acpi_pad ip_table
>>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
>>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
>>>>>>>> mlx5_core igb mlx4_core
>>>>>>>> [  920.412347]  ahci ptp drm libahci pps_core libata dca i2c_algo_bit
>>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
>>>>>>>> [  920.421744] CPU: 11 PID: 705 Comm: kworker/11:2 Not tainted 4.9.0+ #3
>>>>>>>> [  920.428199] Hardware name: Supermicro SYS-6028TP-HTFR/X10DRT-PIBF,
>>>>>>>> BIOS 1.1 08/03/2015
>>>>>>>> [  920.436126] Workqueue: ib_cm cm_work_handler [ib_cm]
>>>>>>>> [  920.441113]  ffffc90032a03a40 ffffffff8134d45f 0000000000000000
>>>>>>>> 0000000000000000
>>>>>>>> [  920.448583]  ffffc90032a03a80 ffffffff81083371 0000012fa04a1c4a
>>>>>>>> ffff883f5e886e80
>>>>>>>> [  920.456073]  ffff887f1eaa4400 ffff887f1eaa5800 ffffc90032a03b08
>>>>>>>> 00000000ffffff92
>>>>>>>> [  920.463535] Call Trace:
>>>>>>>> [  920.465993]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
>>>>>>>> [  920.471144]  [<ffffffff81083371>] __warn+0xd1/0xf0
>>>>>>>> [  920.475941]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
>>>>>>>> [  920.481790]  [<ffffffffa026cf58>] ib_dealloc_pd+0x58/0xa0 [ib_core]
>>>>>>>> [  920.488072]  [<ffffffffa0695000>] isert_device_put+0x50/0xc0 [ib_isert]
>>>>>>>> [  920.494693]  [<ffffffffa069838e>] isert_connect_request+0x68e/0xd40
>>>>>>>> [ib_isert]
>>>>>>>> [  920.501924]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0 [ib_isert]
>>>>>>>> [  920.508725]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0 [rdma_cm]
>>>>>>>> [  920.515521]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30 [rdma_cm]
>>>>>>>> [  920.522227]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0 [rdma_cm]
>>>>>>>> [  920.528851]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0 [ib_cm]
>>>>>>>> [  920.535125]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70 [ib_cm]
>>>>>>>> [  920.541485]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648 [ib_cm]
>>>>>>>> [  920.548021]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
>>>>>>>> [  920.553861]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
>>>>>>>> [  920.559443]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
>>>>>>>> [  920.565284]  [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>> [  920.570178]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
>>>>>>>> [  920.576389]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>> [  920.582473] ---[ end trace 1f5a1831f9d2d964 ]---
>>>>>>>> [  920.587907] ------------[ cut here ]------------
>>>>>>>> [  920.593213] WARNING: CPU: 11 PID: 705 at
>>>>>>>> drivers/infiniband/core/cq.c:189 ib_free_cq+0x97/0xc0 [ib_core]
>>>>>>>> [  920.603383] Modules linked in: target_core_user target_core_pscsi
>>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
>>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
>>>>>>>> iptable_filter rdma_ucm i
>>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
>>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
>>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
>>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
>>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
>>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
>>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
>>>>>>>> acpi_power_meter acpi_pad ip_table
>>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
>>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
>>>>>>>> mlx5_core igb mlx4_core
>>>>>>>> [  920.679694]  ahci ptp drm libahci pps_core libata dca i2c_algo_bit
>>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
>>>>>>>> [  920.690579] CPU: 11 PID: 705 Comm: kworker/11:2 Tainted: G        W
>>>>>>>>       4.9.0+ #3
>>>>>>>> [  920.699008] Hardware name: Supermicro SYS-6028TP-HTFR/X10DRT-PIBF,
>>>>>>>> BIOS 1.1 08/03/2015
>>>>>>>> [  920.707701] Workqueue: ib_cm cm_work_handler [ib_cm]
>>>>>>>> [  920.713438]  ffffc90032a03a18 ffffffff8134d45f 0000000000000000
>>>>>>>> 0000000000000000
>>>>>>>> [  920.721648]  ffffc90032a03a58 ffffffff81083371 000000bd5e886e80
>>>>>>>> ffff887f1eaa6800
>>>>>>>> [  920.729850]  ffff883f5e886e20 ffff883f5e886e18 ffffc90032a03b08
>>>>>>>> 00000000ffffff92
>>>>>>>> [  920.738026] Call Trace:
>>>>>>>> [  920.741188]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
>>>>>>>> [  920.747027]  [<ffffffff81083371>] __warn+0xd1/0xf0
>>>>>>>> [  920.752488]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
>>>>>>>> [  920.758989]  [<ffffffffa026e037>] ib_free_cq+0x97/0xc0 [ib_core]
>>>>>>>> [  920.765649]  [<ffffffffa0694f88>]
>>>>>>>> isert_free_comps.isra.26+0x38/0x60 [ib_isert]
>>>>>>>> [  920.773609]  [<ffffffffa069500d>] isert_device_put+0x5d/0xc0 [ib_isert]
>>>>>>>> [  920.780868]  [<ffffffffa069838e>] isert_connect_request+0x68e/0xd40
>>>>>>>> [ib_isert]
>>>>>>>> [  920.788734]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0 [ib_isert]
>>>>>>>> [  920.796157]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0 [rdma_cm]
>>>>>>>> [  920.803586]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30 [rdma_cm]
>>>>>>>> [  920.810916]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0 [rdma_cm]
>>>>>>>> [  920.818167]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0 [ib_cm]
>>>>>>>> [  920.825063]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70 [ib_cm]
>>>>>>>> [  920.832051]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648 [ib_cm]
>>>>>>>> [  920.839208]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
>>>>>>>> [  920.845669]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
>>>>>>>> [  920.851880]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
>>>>>>>> [  920.858352]  [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>> [  920.863857]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
>>>>>>>> [  920.869975]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>> [  920.876006] ---[ end trace 1f5a1831f9d2d965 ]---
>>>>>>>> [  920.884335] isert: isert_cma_handler: failed handle connect request -110
>>>>>>>> [ 1639.592451] Setting up drain callback.
>>>>>>>> [ 1639.596073] Starting init_completion.
>>>>>>>> [ 1639.600683] Calling ib_modify_qp.
>>>>>>>> [ 1639.602616] Calling ib_post_send.
>>>>>>>> [ 1639.606550] Starting wait_for_completion.
>>>>>>>> [ 1656.976015] iSCSI Login timeout on Network Portal 0.0.0.0:3260
>>>>>>>> [ 1674.254027] Setting up drain callback.
>>>>>>>> [ 1674.257634] Starting init_completion.
>>>>>>>> [ 1674.262107] Calling ib_modify_qp.
>>>>>>>> [ 1674.264011] Calling ib_post_send.
>>>>>>>> [ 1674.267969] Starting wait_for_completion.
>>>>>>>> [ 1691.583888] Setting up drain callback.
>>>>>>>> [ 1691.588490] Starting init_completion.
>>>>>>>> [ 1691.590677] Calling ib_modify_qp.
>>>>>>>> [ 1691.594766] Calling ib_post_send.
>>>>>>>> [ 1691.596607] Starting wait_for_completion.
>>>>>>>> [ 1708.913356] Setting up drain callback.
>>>>>>>> [ 1708.915658] Starting init_completion.
>>>>>>>> [ 1708.920152] Calling ib_modify_qp.
>>>>>>>> [ 1708.922041] Calling ib_post_send.
>>>>>>>> [ 1708.926048] Starting wait_for_completion.
>>>>>>>> [ 1726.244365] Setting up drain callback.
>>>>>>>> [ 1726.248973] Starting init_completion.
>>>>>>>> [ 1726.251165] Calling ib_modify_qp.
>>>>>>>> [ 1726.255189] Calling ib_post_send.
>>>>>>>> [ 1726.257031] Starting wait_for_completion.
>>>>>>>> [ 1743.574751] Setting up drain callback.
>>>>>>>> [ 1743.577044] Starting init_completion.
>>>>>>>> [ 1743.581496] Calling ib_modify_qp.
>>>>>>>> [ 1743.583404] Calling ib_post_send.
>>>>>>>> [ 1743.587346] Starting wait_for_completion.
>>>>>>>> [ 1760.904470] Setting up drain callback.
>>>>>>>> [ 1760.908991] Starting init_completion.
>>>>>>>> [ 1760.911206] Calling ib_modify_qp.
>>>>>>>> [ 1760.915214] Calling ib_post_send.
>>>>>>>> [ 1760.917062] Starting wait_for_completion.
>>>>>>>> [ 1778.230821] Setting up drain callback.
>>>>>>>> [ 1778.233116] Starting init_completion.
>>>>>>>> [ 1778.237510] Calling ib_modify_qp.
>>>>>>>> [ 1778.239413] Calling ib_post_send.
>>>>>>>> .... [keeps repeating]
>>>>>>>> ----------------
>>>>>>>> Robert LeBlanc
>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Dec 22, 2016 at 12:15 PM, Doug Ledford <dledford@redhat.com> wrote:
>>>>>>>>> On 12/21/2016 6:39 PM, Robert LeBlanc wrote:
>>>>>>>>>> I hit a new backtrace today, hopefully it adds something.
>>>>>>>>>>
>>>>>>>>>> # cat /proc/19659/stack
>>>>>>>>>> [<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
>>>>>>>>>> [<ffffffff81521c62>] iscsi_check_for_session_reinstatement+0x1e2/0x270
>>>>>>>>>> [<ffffffff81524660>] iscsi_target_check_for_existing_instances+0x30/0x40
>>>>>>>>>> [<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
>>>>>>>>>> [<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
>>>>>>>>>> [<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
>>>>>>>>>> [<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
>>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>
>>>>>>>>>> # cat /proc/21342/stack
>>>>>>>>>> [<ffffffffa0292b10>] __ib_drain_sq+0x190/0x1c0 [ib_core]
>>>>>>>>>> [<ffffffffa0292b65>] ib_drain_sq+0x25/0x30 [ib_core]
>>>>>>>>>> [<ffffffffa0292d72>] ib_drain_qp+0x12/0x30 [ib_core]
>>>>>>>>>> [<ffffffffa062c5ff>] isert_wait_conn+0x5f/0x2d0 [ib_isert]
>>>>>>>>>> [<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
>>>>>>>>>> [<ffffffff8151f10b>] iscsit_take_action_for_connection_exit+0x7b/0xf0
>>>>>>>>>> [<ffffffff81530265>] iscsi_target_rx_thread+0x95/0xa0
>>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
>>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>
>>>>>>>>>> # ps aux | grep iscsi | grep D
>>>>>>>>>> root     19659  0.0  0.0      0     0 ?        D    16:12   0:00 [iscsi_np]
>>>>>>>>>> root     21342  0.0  0.0      0     0 ?        D    16:29   0:00 [iscsi_trx]
>>>>>>>>>> ----------------
>>>>>>>>>> Robert LeBlanc
>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>
>>>>>>>>> That looks suspiciously like the __ib_drain_sq is stuck forever waiting
>>>>>>>>> on a completion that never comes.
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Thu, Dec 15, 2016 at 1:38 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>>> Nicholas,
>>>>>>>>>>>
>>>>>>>>>>> I've found that the kernels I used were not able to be inspected using
>>>>>>>>>>> crash and I could not build the debug info for them. So I built a new
>>>>>>>>>>> 4.9 kernel and verified that I could inspect the crash. It is located
>>>>>>>>>>> at [1].
>>>>>>>>>>>
>>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash2.tar.xz
>>>>>>>>>>> ----------------
>>>>>>>>>>> Robert LeBlanc
>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Mon, Dec 12, 2016 at 4:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>>>> Nicholas,
>>>>>>>>>>>>
>>>>>>>>>>>> After lots of set backs and having to give up trying to get kernel
>>>>>>>>>>>> dumps on our "production" systems, I've been able to work out the
>>>>>>>>>>>> issues we had with kdump and replicate the issue on my dev boxes. I
>>>>>>>>>>>> have dumps from 4.4.30 and 4.9-rc8 (makedumpfile would not dump, so it
>>>>>>>>>>>> is a straight copy of /proc/vmcore from the crash kernel). In each
>>>>>>>>>>>> crash directory, I put a details.txt file that has the process IDs
>>>>>>>>>>>> that were having problems and a brief description of the set-up at the
>>>>>>>>>>>> time. This was mostly replicated by starting fio and pulling the
>>>>>>>>>>>> Infiniband cable until fio gave up. This hardware also has Mellanox
>>>>>>>>>>>> ConnectX4-LX cards and I also replicated the issue over RoCE using 4.9
>>>>>>>>>>>> since it has the drivers in-box. Please let me know if you need more
>>>>>>>>>>>> info, I can test much faster now. The cores/kernels/modules are
>>>>>>>>>>>> located at [1].
>>>>>>>>>>>>
>>>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash.tar.xz
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Robert
>>>>>>>>>>>> ----------------
>>>>>>>>>>>> Robert LeBlanc
>>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> On Fri, Nov 4, 2016 at 3:57 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
>>>>>>>>>>>>> We hit this yesterday, this time it was on the tx thread (the other
>>>>>>>>>>>>> ones before seem to be on the rx thread). We weren't able to get a
>>>>>>>>>>>>> kernel dump on this. We'll try to get one next time.
>>>>>>>>>>>>>
>>>>>>>>>>>>> # ps axuw | grep "D.*iscs[i]"
>>>>>>>>>>>>> root     12383  0.0  0.0      0     0 ?        D    Nov03   0:04 [iscsi_np]
>>>>>>>>>>>>> root     23016  0.0  0.0      0     0 ?        D    Nov03   0:00 [iscsi_ttx]
>>>>>>>>>>>>> root     23018  0.0  0.0      0     0 ?        D    Nov03   0:00 [iscsi_ttx]
>>>>>>>>>>>>> # cat /proc/12383/stack
>>>>>>>>>>>>> [<ffffffff814f24af>] iscsit_stop_session+0x19f/0x1d0
>>>>>>>>>>>>> [<ffffffff814e3c66>] iscsi_check_for_session_reinstatement+0x1e6/0x270
>>>>>>>>>>>>> [<ffffffff814e6620>] iscsi_target_check_for_existing_instances+0x30/0x40
>>>>>>>>>>>>> [<ffffffff814e6770>] iscsi_target_do_login+0x140/0x640
>>>>>>>>>>>>> [<ffffffff814e7b0c>] iscsi_target_start_negotiation+0x1c/0xb0
>>>>>>>>>>>>> [<ffffffff814e585b>] iscsi_target_login_thread+0xa9b/0xfc0
>>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>>> # cat /proc/23016/stack
>>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
>>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
>>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
>>>>>>>>>>>>> [<ffffffff814e110f>] iscsit_take_action_for_connection_exit+0x7f/0x100
>>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
>>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>>> # cat /proc/23018/stack
>>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
>>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
>>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
>>>>>>>>>>>>> [<ffffffff814e110f>] iscsit_take_action_for_connection_exit+0x7f/0x100
>>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
>>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>>>>>>>>>>
>>>>>>>>>>>>> From dmesg:
>>>>>>>>>>>>> [  394.476332] INFO: rcu_sched self-detected stall on CPU
>>>>>>>>>>>>> [  394.476334]  20-...: (23976 ticks this GP)
>>>>>>>>>>>>> idle=edd/140000000000001/0 softirq=292/292 fqs=18788
>>>>>>>>>>>>> [  394.476336]   (t=24003 jiffies g=3146 c=3145 q=0)
>>>>>>>>>>>>> [  394.476337] Task dump for CPU 20:
>>>>>>>>>>>>> [  394.476338] kworker/u68:2   R  running task        0 12906      2 0x00000008
>>>>>>>>>>>>> [  394.476345] Workqueue: isert_comp_wq isert_cq_work [ib_isert]
>>>>>>>>>>>>> [  394.476346]  ffff883f2fe38000 00000000f805705e ffff883f7fd03da8
>>>>>>>>>>>>> ffffffff810ac8ff
>>>>>>>>>>>>> [  394.476347]  0000000000000014 ffffffff81adb680 ffff883f7fd03dc0
>>>>>>>>>>>>> ffffffff810af239
>>>>>>>>>>>>> [  394.476348]  0000000000000015 ffff883f7fd03df0 ffffffff810e1cd0
>>>>>>>>>>>>> ffff883f7fd17b80
>>>>>>>>>>>>> [  394.476348] Call Trace:
>>>>>>>>>>>>> [  394.476354]  <IRQ>  [<ffffffff810ac8ff>] sched_show_task+0xaf/0x110
>>>>>>>>>>>>> [  394.476355]  [<ffffffff810af239>] dump_cpu_task+0x39/0x40
>>>>>>>>>>>>> [  394.476357]  [<ffffffff810e1cd0>] rcu_dump_cpu_stacks+0x80/0xb0
>>>>>>>>>>>>> [  394.476359]  [<ffffffff810e6100>] rcu_check_callbacks+0x540/0x820
>>>>>>>>>>>>> [  394.476360]  [<ffffffff810afe11>] ? account_system_time+0x81/0x110
>>>>>>>>>>>>> [  394.476363]  [<ffffffff810faa60>] ? tick_sched_do_timer+0x50/0x50
>>>>>>>>>>>>> [  394.476364]  [<ffffffff810eb599>] update_process_times+0x39/0x60
>>>>>>>>>>>>> [  394.476365]  [<ffffffff810fa815>] tick_sched_handle.isra.17+0x25/0x60
>>>>>>>>>>>>> [  394.476366]  [<ffffffff810faa9d>] tick_sched_timer+0x3d/0x70
>>>>>>>>>>>>> [  394.476368]  [<ffffffff810ec182>] __hrtimer_run_queues+0x102/0x290
>>>>>>>>>>>>> [  394.476369]  [<ffffffff810ec668>] hrtimer_interrupt+0xa8/0x1a0
>>>>>>>>>>>>> [  394.476372]  [<ffffffff81052c65>] local_apic_timer_interrupt+0x35/0x60
>>>>>>>>>>>>> [  394.476374]  [<ffffffff8172423d>] smp_apic_timer_interrupt+0x3d/0x50
>>>>>>>>>>>>> [  394.476376]  [<ffffffff817224f7>] apic_timer_interrupt+0x87/0x90
>>>>>>>>>>>>> [  394.476379]  <EOI>  [<ffffffff810d71be>] ? console_unlock+0x41e/0x4e0
>>>>>>>>>>>>> [  394.476380]  [<ffffffff810d757c>] vprintk_emit+0x2fc/0x500
>>>>>>>>>>>>> [  394.476382]  [<ffffffff810d78ff>] vprintk_default+0x1f/0x30
>>>>>>>>>>>>> [  394.476384]  [<ffffffff81174dde>] printk+0x5d/0x74
>>>>>>>>>>>>> [  394.476388]  [<ffffffff814bce21>] transport_lookup_cmd_lun+0x1d1/0x200
>>>>>>>>>>>>> [  394.476390]  [<ffffffff814ee8c0>] iscsit_setup_scsi_cmd+0x230/0x540
>>>>>>>>>>>>> [  394.476392]  [<ffffffffa058dbf3>] isert_rx_do_work+0x3f3/0x7f0 [ib_isert]
>>>>>>>>>>>>> [  394.476394]  [<ffffffffa058e174>] isert_cq_work+0x184/0x770 [ib_isert]
>>>>>>>>>>>>> [  394.476396]  [<ffffffff8109740f>] process_one_work+0x14f/0x400
>>>>>>>>>>>>> [  394.476397]  [<ffffffff81097c84>] worker_thread+0x114/0x470
>>>>>>>>>>>>> [  394.476398]  [<ffffffff8171d32a>] ? __schedule+0x34a/0x7f0
>>>>>>>>>>>>> [  394.476399]  [<ffffffff81097b70>] ? rescuer_thread+0x310/0x310
>>>>>>>>>>>>> [  394.476400]  [<ffffffff8109d7c8>] kthread+0xd8/0xf0
>>>>>>>>>>>>> [  394.476402]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
>>>>>>>>>>>>> [  394.476403]  [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
>>>>>>>>>>>>> [  394.476404]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
>>>>>>>>>>>>> [  405.716632] Unexpected ret: -104 send data 360
>>>>>>>>>>>>> [  405.721711] tx_data returned -32, expecting 360.
>>>>>>>>>>>>> ----------------
>>>>>>>>>>>>> Robert LeBlanc
>>>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
>>>>>>>>>
>>>>>>>>> When you combine this trace with the newest one, it really makes me
>>>>>>>>> thing there is something of a bad interaction between the new drain cq
>>>>>>>>> API and the iser/isert implementation to use said API.  Sagi, Christoph?
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Doug Ledford <dledford@redhat.com>
>>>>>>>>>     GPG Key ID: B826A3330E572FDD
>>>>>>>>>     Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD
>>>>>>>>>
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Laurence Oberman Jan. 6, 2017, 5:06 p.m. UTC | #2
----- Original Message -----
> From: "Robert LeBlanc" <robert@leblancnet.us>
> To: "Doug Ledford" <dledford@redhat.com>
> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>, "Zhu Lingshan" <lszhu@suse.com>, "linux-rdma"
> <linux-rdma@vger.kernel.org>, linux-scsi@vger.kernel.org, "Sagi Grimberg" <sagi@grimberg.me>, "Christoph Hellwig"
> <hch@lst.de>
> Sent: Tuesday, January 3, 2017 7:11:40 PM
> Subject: Re: iscsi_trx going into D state
> 
> With the last patch it is getting hung up on wait_for_completion in
> target_wait_for_sess_cmds. I don't know what t_state or fabric state
> mean. To me it looks like a queue is not being emptied, but it would
> help if someone confirmed this and has some pointers on how to
> properly flush them when the communication is interrupted.
> 
> [  222.989134] Starting iscsit_close_connection.
> [  222.993555] Calling flush_workqueue.
> [  222.997703] Returned from flush_workqueue.
> [  223.005802] isert_wait_conn calling ib_close_qp/ib_drain_qp.
> [  223.011892] isert_wait_conn finished ib_close_qp/ib_drain_qp.
> [  223.018063] isert_wait_conn calling isert_put_unsol_pending_cmds.
> [  223.024574] isert_wait_conn returned from
> isert_put_unsol_pending_cmds.
> [  223.031582] isert_wait_conn calling isert_wait4cmds.
> [  223.036942] isert_wait4cmds calling
> target_sess_cmd_list_set_waiting.
> [  223.043789] isert_wait4cmds returned from
> target_sess_cmd_list_set_waiting.
> [  223.051135] isert_wait4cmds calling target_wait_for_sess_cmds.
> [  223.057362] Waiting for se_cmd: ffff887ebf88bd00 t_state: 6, fabric
> state: 29
> [  223.064893] target_wait_for_sess_cmds calling
> spin_unlock_irqrestore.
> [  223.071748] target_wait_for_sess_cmds calling wait_for_completion.
> [  224.997636] Calling wait_for_common.
> [  225.001936] Starting __wait_for_common.
> [  225.006226] Calling do_wait_for_common.
> 
> Thanks
> ----------------
> Robert LeBlanc
> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> 
> 
> On Tue, Jan 3, 2017 at 1:07 PM, Robert LeBlanc <robert@leblancnet.us> wrote:
> > With this patch I'm not seeing the __ib_drain_sq backtraces, but I'm
> > still seeing the previous backtraces.
> >
> > diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
> > b/drivers/infiniband/ulp/isert/ib_isert.c
> > index 6dd43f6..1e53502 100644
> > --- a/drivers/infiniband/ulp/isert/ib_isert.c
> > +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> > @@ -2595,7 +2595,7 @@ static void isert_wait_conn(struct iscsi_conn *conn)
> >        isert_conn_terminate(isert_conn);
> >        mutex_unlock(&isert_conn->mutex);
> >
> > -       ib_drain_qp(isert_conn->qp);
> > +       ib_close_qp(isert_conn->qp);
> >        isert_put_unsol_pending_cmds(conn);
> >        isert_wait4cmds(conn);
> >        isert_wait4logout(isert_conn);
> >
> > I was thinking that if the connection was brought down uncleanly then
> > there may be messages(??) it the send queue that would never be
> > consumed by the application, so it would never drain and would have to
> > be forcibly emptied. Maybe there is something stuck in the command
> > queue as well?
> >
> > [(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
> > root     15426  0.0  0.0      0     0 ?        D    12:48   0:00 [iscsi_np]
> > root     15429  0.0  0.0      0     0 ?        D    12:48   0:00
> > [iscsi_ttx]
> > root     16077  0.0  0.0 112656  2216 pts/0    S+   12:55   0:00 grep
> > --color=auto  D
> > [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15426/stack
> > [<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
> > [<ffffffff81521c62>] iscsi_check_for_session_reinstatement+0x1e2/0x270
> > [<ffffffff81524660>] iscsi_target_check_for_existing_instances+0x30/0x40
> > [<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
> > [<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
> > [<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
> > [<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
> > [<ffffffff810a3059>] kthread+0xd9/0xf0
> > [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> > [<ffffffffffffffff>] 0xffffffffffffffff
> > [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/15429/stack
> > [<ffffffff8150c689>] target_wait_for_sess_cmds+0x49/0x190
> > [<ffffffffa0705744>] isert_wait_conn+0x1a4/0x2d0 [ib_isert]
> > [<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
> > [<ffffffff8151f10b>] iscsit_take_action_for_connection_exit+0x7b/0xf0
> > [<ffffffff81530150>] iscsi_target_tx_thread+0x150/0x1d0
> > [<ffffffff810a3059>] kthread+0xd9/0xf0
> > [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> > [<ffffffffffffffff>] 0xffffffffffffffff
> > ----------------
> > Robert LeBlanc
> > PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >
> >
> > On Fri, Dec 30, 2016 at 4:07 PM, Robert LeBlanc <robert@leblancnet.us>
> > wrote:
> >> I decided to try something completely different... Running the stock
> >> CentOS 3.10 kernel and OFED 3.4 on both hosts, I'm not seeing the hung
> >> processes and the tests complete successfully. The same seems to be
> >> true for the target on 4.9 and the initiator on 3.10.
> >>
> >> However, with the target on 3.10 and the initiator on 4.9, I get this
> >> on the target:
> >>
> >> [(support-1.0) root@prv-0-13-roberttest ~]# ps aux | grep " D "
> >> root     14791  0.0  0.0      0     0 ?        D    15:08   0:00
> >> [iscsi_np]
> >> root     14795  0.0  0.0      0     0 ?        D    15:08   0:00
> >> [iscsi_trx]
> >> root     14852  0.0  0.0 112648   976 pts/0    S+   15:11   0:00 grep
> >> --color=auto  D
> >> [(support-1.0) root@prv-0-13-roberttest ~]# uname -a
> >> Linux prv-0-13-roberttest.betterservers.com 3.10.0-327.36.3.el7.x86_64
> >> #1 SMP Mon Oct 24 16:09:20 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
> >> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14791/stack
> >> [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0 [iscsi_target_mod]
> >> [<ffffffffa09ceefa>] iscsi_check_for_session_reinstatement+0x1ea/0x280
> >> [iscsi_target_mod]
> >> [<ffffffffa09d19f5>]
> >> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
> >> [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670 [iscsi_target_mod]
> >> [<ffffffffa09d2f4c>] iscsi_target_start_negotiation+0x1c/0xb0
> >> [iscsi_target_mod]
> >> [<ffffffffa09d0c6f>] iscsi_target_login_thread+0xadf/0x1050
> >> [iscsi_target_mod]
> >> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> >> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> >> [<ffffffffffffffff>] 0xffffffffffffffff
> >> [(support-1.0) root@prv-0-13-roberttest ~]# cat /proc/14795/stack
> >> [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
> >> [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
> >> [<ffffffffa09ddfbd>] iscsit_close_connection+0x15d/0x820
> >> [iscsi_target_mod]
> >> [<ffffffffa09cc183>] iscsit_take_action_for_connection_exit+0x83/0x110
> >> [iscsi_target_mod]
> >> [<ffffffffa09dccb7>] iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
> >> [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> >> [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> >> [<ffffffffffffffff>] 0xffffffffffffffff
> >>
> >> [  345.970157] iSCSI Login timeout on Network Portal 0.0.0.0:3260
> >> [  483.850714] INFO: task iscsi_np:14791 blocked for more than 120
> >> seconds.
> >> [  483.857467] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >> disables this message.
> >> [  483.865326] iscsi_np        D 0000000000000000     0 14791      2
> >> 0x00000004
> >> [  483.872460]  ffff886e3b117be0 0000000000000046 ffff887ede579700
> >> ffff886e3b117fd8
> >> [  483.879983]  ffff886e3b117fd8 ffff886e3b117fd8 ffff887ede579700
> >> ffff883ef7898160
> >> [  483.887500]  ffff883ef7898168 7fffffffffffffff ffff887ede579700
> >> 0000000000000000
> >> [  483.895025] Call Trace:
> >> [  483.897505]  [<ffffffff8163bb39>] schedule+0x29/0x70
> >> [  483.902496]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
> >> [  483.908355]  [<ffffffff812fc60b>] ? simple_strtoull+0x3b/0x70
> >> [  483.914128]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
> >> [  483.920253]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
> >> [  483.925847]  [<ffffffffa09dde48>] iscsit_stop_session+0x1c8/0x1e0
> >> [iscsi_target_mod]
> >> [  483.933612]  [<ffffffffa09ceefa>]
> >> iscsi_check_for_session_reinstatement+0x1ea/0x280 [iscsi_target_mod]
> >> [  483.942944]  [<ffffffffa09d19f5>]
> >> iscsi_target_check_for_existing_instances+0x35/0x40 [iscsi_target_mod]
> >> [  483.953304]  [<ffffffffa09d1b41>] iscsi_target_do_login+0x141/0x670
> >> [iscsi_target_mod]
> >> [  483.961988]  [<ffffffffa09d2f4c>]
> >> iscsi_target_start_negotiation+0x1c/0xb0 [iscsi_target_mod]
> >> [  483.971278]  [<ffffffffa09d0c6f>]
> >> iscsi_target_login_thread+0xadf/0x1050 [iscsi_target_mod]
> >> [  483.980346]  [<ffffffff8163b401>] ? __schedule+0x1f1/0x900
> >> [  483.986525]  [<ffffffffa09d0190>] ?
> >> iscsi_target_login_sess_out+0x250/0x250 [iscsi_target_mod]
> >> [  483.995816]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> >> [  484.001403]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> >> [  484.008608]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> >> [  484.014672]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> >> [  484.021896] INFO: task iscsi_trx:14795 blocked for more than 120
> >> seconds.
> >> [  484.029349] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >> disables this message.
> >> [  484.037849] iscsi_trx       D ffff887ee64f8000     0 14795      2
> >> 0x00000004
> >> [  484.045598]  ffff886e391bfbe0 0000000000000046 ffff887ed715c500
> >> ffff886e391bffd8
> >> [  484.053753]  ffff886e391bffd8 ffff886e391bffd8 ffff887ed715c500
> >> ffff887ee64f91d0
> >> [  484.061891]  ffff887ee64f91d8 7fffffffffffffff ffff887ed715c500
> >> ffff887ee64f8000
> >> [  484.070049] Call Trace:
> >> [  484.073174]  [<ffffffff8163bb39>] schedule+0x29/0x70
> >> [  484.078797]  [<ffffffff81639829>] schedule_timeout+0x209/0x2d0
> >> [  484.085290]  [<ffffffffa0672125>] ? cm_alloc_msg+0x115/0x180 [ib_cm]
> >> [  484.092252]  [<ffffffff8163bf06>] wait_for_completion+0x116/0x170
> >> [  484.098960]  [<ffffffff810b8940>] ? wake_up_state+0x20/0x20
> >> [  484.105132]  [<ffffffffa0801469>] isert_wait4flush+0x79/0xc0 [ib_isert]
> >> [  484.112369]  [<ffffffffa080150b>] isert_wait_conn+0x5b/0x2d0 [ib_isert]
> >> [  484.119566]  [<ffffffffa09ddfbd>]
> >> iscsit_close_connection+0x15d/0x820 [iscsi_target_mod]
> >> [  484.128239]  [<ffffffff8163ca67>] ?
> >> wait_for_completion_interruptible+0x167/0x1d0
> >> [  484.136341]  [<ffffffffa09dcad0>] ?
> >> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
> >> [  484.145135]  [<ffffffffa09cc183>]
> >> iscsit_take_action_for_connection_exit+0x83/0x110 [iscsi_target_mod]
> >> [  484.155067]  [<ffffffffa09dccb7>]
> >> iscsi_target_rx_thread+0x1e7/0xf80 [iscsi_target_mod]
> >> [  484.163700]  [<ffffffff81013588>] ? __switch_to+0xf8/0x4b0
> >> [  484.169774]  [<ffffffffa09dcad0>] ?
> >> iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
> >> [  484.178530]  [<ffffffff810a5b8f>] kthread+0xcf/0xe0
> >> [  484.183991]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> >> [  484.191106]  [<ffffffff81646a98>] ret_from_fork+0x58/0x90
> >> [  484.197096]  [<ffffffff810a5ac0>] ? kthread_create_on_node+0x140/0x140
> >>
> >> I think there are two bugs here. Something in 4.9 iser (initiator) is
> >> causing a shutdown of the session when limited to 10 Gb. This second
> >> is in isert (target) where when a session isn't cleanly closed, it
> >> gets hung on cleaning up the session. It seems that bug #1 triggers
> >> bug #2 much easier than on Infiniband.
> >>
> >> I hope this is useful.
> >>
> >> ----------------
> >> Robert LeBlanc
> >> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>
> >>
> >> On Thu, Dec 29, 2016 at 4:57 PM, Robert LeBlanc <robert@leblancnet.us>
> >> wrote:
> >>> OK, I've drilled down a little more and
> >>>
> >>> timeout = action(timeout);
> >>>
> >>> in do_wait_for_common() in kernel/sched/completion.c is not returning.
> >>> I'll have to see if I can make more progress tomorrow.
> >>> ----------------
> >>> Robert LeBlanc
> >>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>
> >>>
> >>> On Thu, Dec 29, 2016 at 2:23 PM, Robert LeBlanc <robert@leblancnet.us>
> >>> wrote:
> >>>> I know most people are ignoring this thread by now, but I hope someone
> >>>> is still reading and can offer some ideas.
> >>>>
> >>>> It looks like ib_drain_qp_done() is not being called the first time
> >>>> that __ib_drain_sq() is called from iscsit_close_connection(). I tried
> >>>> to debug wait_for_completion() and friends, but they are called by too
> >>>> many things and I don't know how to filter out what I'm looking for.
> >>>> My next idea is to copy the completion functions here so that I can
> >>>> add debug to only that path. I feel like I'm inching closer to the
> >>>> problem, stumbling around in the dark.
> >>>>
> >>>> [Thu Dec 29 14:02:03 2016] Starting iscsit_close_connection.
> >>>> [Thu Dec 29 14:02:03 2016] isert_wait_conn calling ib_drain_qp.
> >>>> [Thu Dec 29 14:02:03 2016] ib_drain_qp calling ib_drain_sq.
> >>>> [Thu Dec 29 14:02:03 2016] ib_drain_sq calling __ib_drain_sq.
> >>>> [Thu Dec 29 14:02:03 2016] Setting up drain callback.
> >>>> [Thu Dec 29 14:02:03 2016] Starting init_completion.
> >>>> [Thu Dec 29 14:02:03 2016] Calling ib_modify_qp.
> >>>> [Thu Dec 29 14:02:03 2016] Calling ib_post_send.
> >>>> [Thu Dec 29 14:02:03 2016] Calling wait_for_completion.
> >>>> [Thu Dec 29 14:02:03 2016] &sdrain.done->done = 0.
> >>>>
> >>>> Gets "stuck" here...
> >>>>
> >>>> [Thu Dec 29 14:02:20 2016] iSCSI Login timeout on Network Portal
> >>>> 0.0.0.0:3260
> >>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp calling ib_drain_sq.
> >>>> [Thu Dec 29 14:02:37 2016] ib_drain_sq calling __ib_drain_sq.
> >>>> [Thu Dec 29 14:02:37 2016] Setting up drain callback.
> >>>> [Thu Dec 29 14:02:37 2016] Starting init_completion.
> >>>> [Thu Dec 29 14:02:37 2016] Calling ib_modify_qp.
> >>>> [Thu Dec 29 14:02:37 2016] Calling ib_post_send.
> >>>> [Thu Dec 29 14:02:37 2016] Calling wait_for_completion.
> >>>> [Thu Dec 29 14:02:37 2016] ib_drain_qp_done going to call complete.
> >>>> [Thu Dec 29 14:02:38 2016] &sdrain.done->done = 1.
> >>>> [Thu Dec 29 14:02:38 2016] Returned from wait_for_completion.
> >>>> [Thu Dec 29 14:02:38 2016] ib_drain_qp_done going to call complete.
> >>>>
> >>>> Next time ib_drain_qp is called, ib_drain_qp_done gets called...
> >>>>
> >>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp calling ib_drain_sq.
> >>>> [Thu Dec 29 14:02:55 2016] ib_drain_sq calling __ib_drain_sq.
> >>>> [Thu Dec 29 14:02:55 2016] Setting up drain callback.
> >>>> [Thu Dec 29 14:02:55 2016] Starting init_completion.
> >>>> [Thu Dec 29 14:02:55 2016] Calling ib_modify_qp.
> >>>> [Thu Dec 29 14:02:55 2016] Calling ib_post_send.
> >>>> [Thu Dec 29 14:02:55 2016] Calling wait_for_completion.
> >>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
> >>>> [Thu Dec 29 14:02:55 2016] &sdrain.done->done = 1.
> >>>> [Thu Dec 29 14:02:55 2016] Returned from wait_for_completion.
> >>>> [Thu Dec 29 14:02:55 2016] ib_drain_qp_done going to call complete.
> >>>> ----------------
> >>>> Robert LeBlanc
> >>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>
> >>>>
> >>>> On Wed, Dec 28, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us>
> >>>> wrote:
> >>>>> Good news! I found a 10 Gb switch laying around and put it in place of
> >>>>> the Linux router. I'm getting the same failure with the switch, so it
> >>>>> is not something funky with the Linux router and easier to replicate.
> >>>>> ----------------
> >>>>> Robert LeBlanc
> >>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>>
> >>>>>
> >>>>> On Wed, Dec 28, 2016 at 1:39 PM, Robert LeBlanc <robert@leblancnet.us>
> >>>>> wrote:
> >>>>>> OK, here is some more info. This is a diagram of my current set up.
> >>>>>>
> >>>>>>                 +----------------+
> >>>>>>                 |  Linux Router  |
> >>>>>>                 |   ConnectX-3   |
> >>>>>>                 | port 1  port 2 |
> >>>>>>                 +----------------+
> >>>>>>                      /      \
> >>>>>> +---------------+   /        \   +---------------+
> >>>>>> |    Host 1     |  / A      A \  |    Host 2     |
> >>>>>> | ConnectX-4-LX | /            \ | ConnectX-4-LX |
> >>>>>> |        Port 1 |-              -| Port 1        |
> >>>>>> |        Port 2 |----------------| Port 2        |
> >>>>>> +---------------+        B       +---------------+
> >>>>>>
> >>>>>> The Linux router has the ConnectX-3 (not PRO) card in Ethernet mode
> >>>>>> and is using a breakout cable (port 1 only) to connect to the
> >>>>>> ConnectX-4-LX cards at 10 Gb as path 'A'. The second port of the
> >>>>>> ConnectX-4-LX cards are connected directly at 25 Gb as path 'B'.
> >>>>>>
> >>>>>> Running Iser and RoCE on path 'B' seems to run just fine.
> >>>>>>
> >>>>>> Running Iser and RoCE on path 'A' has issues when the Linux router is
> >>>>>> operating as a bridge or a router. Some small operations like mkfs
> >>>>>> seem to work just fine, but fio causes iser to want to log out and we
> >>>>>> get D state. I can run ib_send_bw 'all' tests through path 'A' and
> >>>>>> don't see a problem. It does seem to be load related, though. I have
> >>>>>> been trying to run
> >>>>>>
> >>>>>> echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K --size=1G
> >>>>>> --numjobs=40 --name=worker.matt --group_reporting
> >>>>>>
> >>>>>> If I reduce the number of jobs to 10 or less, it seems to work
> >>>>>> although I may see some of the debug messages I added in, it doesn't
> >>>>>> seem to completely hang and cause the logout lockup.
> >>>>>>
> >>>>>> Steps to reproduce:
> >>>>>> 1. 4.9 kernel
> >>>>>> 2. Bridge ports 1 & 2 on the Linux router
> >>>>>> 3. Configure port 1 on Host 1 & 2 on the same subnet
> >>>>>> 4. Create large ramdisk in targetcli and export from Host 1
> >>>>>> 5. Login from Host 2
> >>>>>> 6. Create EXT4 file system on imported disk
> >>>>>> 7. Mount and cd into mount
> >>>>>> 8. Run fio: echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K
> >>>>>> --size=1G --numjobs=40 --name=worker.matt --group_reporting
> >>>>>> 9. After some time, the fio process will report the file system is
> >>>>>> read only and the iscsi processes will be in D state on Host 1
> >>>>>>
> >>>>>> It does seem the problem is in iser and not specific to the generic
> >>>>>> RDMA stack.
> >>>>>>
> >>>>>> I'll keep digging and reporting back.
> >>>>>> ----------------
> >>>>>> Robert LeBlanc
> >>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>>>
> >>>>>>
> >>>>>> On Tue, Dec 27, 2016 at 1:58 PM, Robert LeBlanc <robert@leblancnet.us>
> >>>>>> wrote:
> >>>>>>> I realized that I did not set the default RoCE mode to v2 and the
> >>>>>>> client is on a different subnet, probably why I'm seeing the -110
> >>>>>>> error. Iser should not go into D state because of this and should
> >>>>>>> handle this gracefully, but may provide an easy way to replicate the
> >>>>>>> issue.
> >>>>>>> ----------------
> >>>>>>> Robert LeBlanc
> >>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>>>>
> >>>>>>>
> >>>>>>> On Tue, Dec 27, 2016 at 1:22 PM, Robert LeBlanc
> >>>>>>> <robert@leblancnet.us> wrote:
> >>>>>>>> I looked at this code and it is quiet above my ability. I created
> >>>>>>>> this
> >>>>>>>> patch, but I don't know how to interrogate the queue to see how many
> >>>>>>>> items there are. If you can give me some more direction on what to
> >>>>>>>> try, I can keep fumbling around with this until someone smarter than
> >>>>>>>> me can figure it out. This is now a blocker for me so I'm going to
> >>>>>>>> beat my head on this until it is fixed.
> >>>>>>>>
> >>>>>>>> Thanks for being patient with me.
> >>>>>>>>
> >>>>>>>> diff --git a/drivers/infiniband/core/verbs.c
> >>>>>>>> b/drivers/infiniband/core/verbs.c
> >>>>>>>> index 8368764..9e5bd4b 100644
> >>>>>>>> --- a/drivers/infiniband/core/verbs.c
> >>>>>>>> +++ b/drivers/infiniband/core/verbs.c
> >>>>>>>> @@ -1954,22 +1954,27 @@ static void __ib_drain_sq(struct ib_qp *qp)
> >>>>>>>>                 return;
> >>>>>>>>         }
> >>>>>>>>
> >>>>>>>> +       printk("Setting up drain callback.");
> >>>>>>>>         swr.wr_cqe = &sdrain.cqe;
> >>>>>>>>         sdrain.cqe.done = ib_drain_qp_done;
> >>>>>>>> +       printk("Starting init_completion.");
> >>>>>>>>         init_completion(&sdrain.done);
> >>>>>>>>
> >>>>>>>> +       printk("Calling ib_modify_qp.");
> >>>>>>>>         ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
> >>>>>>>>         if (ret) {
> >>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n",
> >>>>>>>>                 ret);
> >>>>>>>>                 return;
> >>>>>>>>         }
> >>>>>>>>
> >>>>>>>> +       printk("Calling ib_post_send.");
> >>>>>>>>         ret = ib_post_send(qp, &swr, &bad_swr);
> >>>>>>>>         if (ret) {
> >>>>>>>>                 WARN_ONCE(ret, "failed to drain send queue: %d\n",
> >>>>>>>>                 ret);
> >>>>>>>>                 return;
> >>>>>>>>         }
> >>>>>>>>
> >>>>>>>> +       printk("Starting wait_for_completion.");
> >>>>>>>>         wait_for_completion(&sdrain.done);
> >>>>>>>>  }
> >>>>>>>>
> >>>>>>>> I get the same processes in D state (and same backtrace) and this is
> >>>>>>>> what shows up in dmesg:
> >>>>>>>>
> >>>>>>>> [  920.317401] isert: isert_rdma_accept: rdma_accept() failed with:
> >>>>>>>> -110
> >>>>>>>> [  920.325554] ------------[ cut here ]------------
> >>>>>>>> [  920.330188] WARNING: CPU: 11 PID: 705 at
> >>>>>>>> drivers/infiniband/core/verbs.c:303 ib_dealloc_pd+0x58/0xa0
> >>>>>>>> [ib_core]
> >>>>>>>> [  920.340210] Modules linked in: target_core_user target_core_pscsi
> >>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
> >>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
> >>>>>>>> iptable_filter rdma_ucm i
> >>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
> >>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
> >>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
> >>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
> >>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
> >>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
> >>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
> >>>>>>>> acpi_power_meter acpi_pad ip_table
> >>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
> >>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
> >>>>>>>> mlx5_core igb mlx4_core
> >>>>>>>> [  920.412347]  ahci ptp drm libahci pps_core libata dca
> >>>>>>>> i2c_algo_bit
> >>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
> >>>>>>>> [  920.421744] CPU: 11 PID: 705 Comm: kworker/11:2 Not tainted
> >>>>>>>> 4.9.0+ #3
> >>>>>>>> [  920.428199] Hardware name: Supermicro
> >>>>>>>> SYS-6028TP-HTFR/X10DRT-PIBF,
> >>>>>>>> BIOS 1.1 08/03/2015
> >>>>>>>> [  920.436126] Workqueue: ib_cm cm_work_handler [ib_cm]
> >>>>>>>> [  920.441113]  ffffc90032a03a40 ffffffff8134d45f 0000000000000000
> >>>>>>>> 0000000000000000
> >>>>>>>> [  920.448583]  ffffc90032a03a80 ffffffff81083371 0000012fa04a1c4a
> >>>>>>>> ffff883f5e886e80
> >>>>>>>> [  920.456073]  ffff887f1eaa4400 ffff887f1eaa5800 ffffc90032a03b08
> >>>>>>>> 00000000ffffff92
> >>>>>>>> [  920.463535] Call Trace:
> >>>>>>>> [  920.465993]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
> >>>>>>>> [  920.471144]  [<ffffffff81083371>] __warn+0xd1/0xf0
> >>>>>>>> [  920.475941]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
> >>>>>>>> [  920.481790]  [<ffffffffa026cf58>] ib_dealloc_pd+0x58/0xa0
> >>>>>>>> [ib_core]
> >>>>>>>> [  920.488072]  [<ffffffffa0695000>] isert_device_put+0x50/0xc0
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.494693]  [<ffffffffa069838e>]
> >>>>>>>> isert_connect_request+0x68e/0xd40
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.501924]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.508725]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.515521]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.522227]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.528851]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.535125]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.541485]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.548021]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
> >>>>>>>> [  920.553861]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
> >>>>>>>> [  920.559443]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
> >>>>>>>> [  920.565284]  [<ffffffff810a3059>] kthread+0xd9/0xf0
> >>>>>>>> [  920.570178]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
> >>>>>>>> [  920.576389]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> >>>>>>>> [  920.582473] ---[ end trace 1f5a1831f9d2d964 ]---
> >>>>>>>> [  920.587907] ------------[ cut here ]------------
> >>>>>>>> [  920.593213] WARNING: CPU: 11 PID: 705 at
> >>>>>>>> drivers/infiniband/core/cq.c:189 ib_free_cq+0x97/0xc0 [ib_core]
> >>>>>>>> [  920.603383] Modules linked in: target_core_user target_core_pscsi
> >>>>>>>> target_core_file target_core_iblock 8021q garp mrp rpcrdma sunrpc
> >>>>>>>> ib_isert ib_iser ib_srpt ib_srp scsi_transport_srp ib_ipoib
> >>>>>>>> iptable_filter rdma_ucm i
> >>>>>>>> b_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm sb_edac edac_core
> >>>>>>>> x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ext4
> >>>>>>>> ipmi_devintf irqbypass crct10dif_pclmul crc32_pclmul
> >>>>>>>> ghash_clmulni_intel aesni_intel jbd2 lr
> >>>>>>>> w gf128mul glue_helper mbcache iTCO_wdt ablk_helper mei_me
> >>>>>>>> iTCO_vendor_support cryptd joydev sg mei i2c_i801 lpc_ich pcspkr
> >>>>>>>> mfd_core ioatdma shpchp i2c_smbus ipmi_si wmi ipmi_msghandler
> >>>>>>>> acpi_power_meter acpi_pad ip_table
> >>>>>>>> s xfs libcrc32c raid1 mlx4_en mlx4_ib mlx5_ib sd_mod ib_core ast
> >>>>>>>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm
> >>>>>>>> mlx5_core igb mlx4_core
> >>>>>>>> [  920.679694]  ahci ptp drm libahci pps_core libata dca
> >>>>>>>> i2c_algo_bit
> >>>>>>>> be2iscsi bnx2i cnic uio qla4xxx iscsi_boot_sysfs
> >>>>>>>> [  920.690579] CPU: 11 PID: 705 Comm: kworker/11:2 Tainted: G
> >>>>>>>> W
> >>>>>>>>       4.9.0+ #3
> >>>>>>>> [  920.699008] Hardware name: Supermicro
> >>>>>>>> SYS-6028TP-HTFR/X10DRT-PIBF,
> >>>>>>>> BIOS 1.1 08/03/2015
> >>>>>>>> [  920.707701] Workqueue: ib_cm cm_work_handler [ib_cm]
> >>>>>>>> [  920.713438]  ffffc90032a03a18 ffffffff8134d45f 0000000000000000
> >>>>>>>> 0000000000000000
> >>>>>>>> [  920.721648]  ffffc90032a03a58 ffffffff81083371 000000bd5e886e80
> >>>>>>>> ffff887f1eaa6800
> >>>>>>>> [  920.729850]  ffff883f5e886e20 ffff883f5e886e18 ffffc90032a03b08
> >>>>>>>> 00000000ffffff92
> >>>>>>>> [  920.738026] Call Trace:
> >>>>>>>> [  920.741188]  [<ffffffff8134d45f>] dump_stack+0x63/0x84
> >>>>>>>> [  920.747027]  [<ffffffff81083371>] __warn+0xd1/0xf0
> >>>>>>>> [  920.752488]  [<ffffffff810834ad>] warn_slowpath_null+0x1d/0x20
> >>>>>>>> [  920.758989]  [<ffffffffa026e037>] ib_free_cq+0x97/0xc0 [ib_core]
> >>>>>>>> [  920.765649]  [<ffffffffa0694f88>]
> >>>>>>>> isert_free_comps.isra.26+0x38/0x60 [ib_isert]
> >>>>>>>> [  920.773609]  [<ffffffffa069500d>] isert_device_put+0x5d/0xc0
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.780868]  [<ffffffffa069838e>]
> >>>>>>>> isert_connect_request+0x68e/0xd40
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.788734]  [<ffffffffa0699683>] isert_cma_handler+0xe3/0x3b0
> >>>>>>>> [ib_isert]
> >>>>>>>> [  920.796157]  [<ffffffffa042c5d6>] ? cma_new_conn_id+0x276/0x4b0
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.803586]  [<ffffffffa0427050>] cma_listen_handler+0x20/0x30
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.810916]  [<ffffffffa042ca05>] cma_req_handler+0x1f5/0x4c0
> >>>>>>>> [rdma_cm]
> >>>>>>>> [  920.818167]  [<ffffffffa03fb0f5>] cm_process_work+0x25/0xf0
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.825063]  [<ffffffffa03fba94>] cm_req_handler+0x8d4/0xc70
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.832051]  [<ffffffffa03fc1ce>] cm_work_handler+0x1ce/0x1648
> >>>>>>>> [ib_cm]
> >>>>>>>> [  920.839208]  [<ffffffff8109cc02>] process_one_work+0x152/0x400
> >>>>>>>> [  920.845669]  [<ffffffff8109d4f5>] worker_thread+0x125/0x4b0
> >>>>>>>> [  920.851880]  [<ffffffff8109d3d0>] ? rescuer_thread+0x380/0x380
> >>>>>>>> [  920.858352]  [<ffffffff810a3059>] kthread+0xd9/0xf0
> >>>>>>>> [  920.863857]  [<ffffffff810a2f80>] ? kthread_park+0x60/0x60
> >>>>>>>> [  920.869975]  [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> >>>>>>>> [  920.876006] ---[ end trace 1f5a1831f9d2d965 ]---
> >>>>>>>> [  920.884335] isert: isert_cma_handler: failed handle connect
> >>>>>>>> request -110
> >>>>>>>> [ 1639.592451] Setting up drain callback.
> >>>>>>>> [ 1639.596073] Starting init_completion.
> >>>>>>>> [ 1639.600683] Calling ib_modify_qp.
> >>>>>>>> [ 1639.602616] Calling ib_post_send.
> >>>>>>>> [ 1639.606550] Starting wait_for_completion.
> >>>>>>>> [ 1656.976015] iSCSI Login timeout on Network Portal 0.0.0.0:3260
> >>>>>>>> [ 1674.254027] Setting up drain callback.
> >>>>>>>> [ 1674.257634] Starting init_completion.
> >>>>>>>> [ 1674.262107] Calling ib_modify_qp.
> >>>>>>>> [ 1674.264011] Calling ib_post_send.
> >>>>>>>> [ 1674.267969] Starting wait_for_completion.
> >>>>>>>> [ 1691.583888] Setting up drain callback.
> >>>>>>>> [ 1691.588490] Starting init_completion.
> >>>>>>>> [ 1691.590677] Calling ib_modify_qp.
> >>>>>>>> [ 1691.594766] Calling ib_post_send.
> >>>>>>>> [ 1691.596607] Starting wait_for_completion.
> >>>>>>>> [ 1708.913356] Setting up drain callback.
> >>>>>>>> [ 1708.915658] Starting init_completion.
> >>>>>>>> [ 1708.920152] Calling ib_modify_qp.
> >>>>>>>> [ 1708.922041] Calling ib_post_send.
> >>>>>>>> [ 1708.926048] Starting wait_for_completion.
> >>>>>>>> [ 1726.244365] Setting up drain callback.
> >>>>>>>> [ 1726.248973] Starting init_completion.
> >>>>>>>> [ 1726.251165] Calling ib_modify_qp.
> >>>>>>>> [ 1726.255189] Calling ib_post_send.
> >>>>>>>> [ 1726.257031] Starting wait_for_completion.
> >>>>>>>> [ 1743.574751] Setting up drain callback.
> >>>>>>>> [ 1743.577044] Starting init_completion.
> >>>>>>>> [ 1743.581496] Calling ib_modify_qp.
> >>>>>>>> [ 1743.583404] Calling ib_post_send.
> >>>>>>>> [ 1743.587346] Starting wait_for_completion.
> >>>>>>>> [ 1760.904470] Setting up drain callback.
> >>>>>>>> [ 1760.908991] Starting init_completion.
> >>>>>>>> [ 1760.911206] Calling ib_modify_qp.
> >>>>>>>> [ 1760.915214] Calling ib_post_send.
> >>>>>>>> [ 1760.917062] Starting wait_for_completion.
> >>>>>>>> [ 1778.230821] Setting up drain callback.
> >>>>>>>> [ 1778.233116] Starting init_completion.
> >>>>>>>> [ 1778.237510] Calling ib_modify_qp.
> >>>>>>>> [ 1778.239413] Calling ib_post_send.
> >>>>>>>> .... [keeps repeating]
> >>>>>>>> ----------------
> >>>>>>>> Robert LeBlanc
> >>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> On Thu, Dec 22, 2016 at 12:15 PM, Doug Ledford <dledford@redhat.com>
> >>>>>>>> wrote:
> >>>>>>>>> On 12/21/2016 6:39 PM, Robert LeBlanc wrote:
> >>>>>>>>>> I hit a new backtrace today, hopefully it adds something.
> >>>>>>>>>>
> >>>>>>>>>> # cat /proc/19659/stack
> >>>>>>>>>> [<ffffffff815304d1>] iscsit_stop_session+0x1b1/0x1c0
> >>>>>>>>>> [<ffffffff81521c62>]
> >>>>>>>>>> iscsi_check_for_session_reinstatement+0x1e2/0x270
> >>>>>>>>>> [<ffffffff81524660>]
> >>>>>>>>>> iscsi_target_check_for_existing_instances+0x30/0x40
> >>>>>>>>>> [<ffffffff815247a8>] iscsi_target_do_login+0x138/0x630
> >>>>>>>>>> [<ffffffff815259be>] iscsi_target_start_negotiation+0x4e/0xa0
> >>>>>>>>>> [<ffffffff8152355e>] __iscsi_target_login_thread+0x83e/0xf20
> >>>>>>>>>> [<ffffffff81523c64>] iscsi_target_login_thread+0x24/0x30
> >>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
> >>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> >>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
> >>>>>>>>>>
> >>>>>>>>>> # cat /proc/21342/stack
> >>>>>>>>>> [<ffffffffa0292b10>] __ib_drain_sq+0x190/0x1c0 [ib_core]
> >>>>>>>>>> [<ffffffffa0292b65>] ib_drain_sq+0x25/0x30 [ib_core]
> >>>>>>>>>> [<ffffffffa0292d72>] ib_drain_qp+0x12/0x30 [ib_core]
> >>>>>>>>>> [<ffffffffa062c5ff>] isert_wait_conn+0x5f/0x2d0 [ib_isert]
> >>>>>>>>>> [<ffffffff815309b7>] iscsit_close_connection+0x157/0x860
> >>>>>>>>>> [<ffffffff8151f10b>]
> >>>>>>>>>> iscsit_take_action_for_connection_exit+0x7b/0xf0
> >>>>>>>>>> [<ffffffff81530265>] iscsi_target_rx_thread+0x95/0xa0
> >>>>>>>>>> [<ffffffff810a3059>] kthread+0xd9/0xf0
> >>>>>>>>>> [<ffffffff817732d5>] ret_from_fork+0x25/0x30
> >>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
> >>>>>>>>>>
> >>>>>>>>>> # ps aux | grep iscsi | grep D
> >>>>>>>>>> root     19659  0.0  0.0      0     0 ?        D    16:12   0:00
> >>>>>>>>>> [iscsi_np]
> >>>>>>>>>> root     21342  0.0  0.0      0     0 ?        D    16:29   0:00
> >>>>>>>>>> [iscsi_trx]
> >>>>>>>>>> ----------------
> >>>>>>>>>> Robert LeBlanc
> >>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
> >>>>>>>>>
> >>>>>>>>> That looks suspiciously like the __ib_drain_sq is stuck forever
> >>>>>>>>> waiting
> >>>>>>>>> on a completion that never comes.
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> On Thu, Dec 15, 2016 at 1:38 PM, Robert LeBlanc
> >>>>>>>>>> <robert@leblancnet.us> wrote:
> >>>>>>>>>>> Nicholas,
> >>>>>>>>>>>
> >>>>>>>>>>> I've found that the kernels I used were not able to be inspected
> >>>>>>>>>>> using
> >>>>>>>>>>> crash and I could not build the debug info for them. So I built a
> >>>>>>>>>>> new
> >>>>>>>>>>> 4.9 kernel and verified that I could inspect the crash. It is
> >>>>>>>>>>> located
> >>>>>>>>>>> at [1].
> >>>>>>>>>>>
> >>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash2.tar.xz
> >>>>>>>>>>> ----------------
> >>>>>>>>>>> Robert LeBlanc
> >>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62
> >>>>>>>>>>> B9F1
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>> On Mon, Dec 12, 2016 at 4:57 PM, Robert LeBlanc
> >>>>>>>>>>> <robert@leblancnet.us> wrote:
> >>>>>>>>>>>> Nicholas,
> >>>>>>>>>>>>
> >>>>>>>>>>>> After lots of set backs and having to give up trying to get
> >>>>>>>>>>>> kernel
> >>>>>>>>>>>> dumps on our "production" systems, I've been able to work out
> >>>>>>>>>>>> the
> >>>>>>>>>>>> issues we had with kdump and replicate the issue on my dev
> >>>>>>>>>>>> boxes. I
> >>>>>>>>>>>> have dumps from 4.4.30 and 4.9-rc8 (makedumpfile would not dump,
> >>>>>>>>>>>> so it
> >>>>>>>>>>>> is a straight copy of /proc/vmcore from the crash kernel). In
> >>>>>>>>>>>> each
> >>>>>>>>>>>> crash directory, I put a details.txt file that has the process
> >>>>>>>>>>>> IDs
> >>>>>>>>>>>> that were having problems and a brief description of the set-up
> >>>>>>>>>>>> at the
> >>>>>>>>>>>> time. This was mostly replicated by starting fio and pulling the
> >>>>>>>>>>>> Infiniband cable until fio gave up. This hardware also has
> >>>>>>>>>>>> Mellanox
> >>>>>>>>>>>> ConnectX4-LX cards and I also replicated the issue over RoCE
> >>>>>>>>>>>> using 4.9
> >>>>>>>>>>>> since it has the drivers in-box. Please let me know if you need
> >>>>>>>>>>>> more
> >>>>>>>>>>>> info, I can test much faster now. The cores/kernels/modules are
> >>>>>>>>>>>> located at [1].
> >>>>>>>>>>>>
> >>>>>>>>>>>> [1] http://mirrors.betterservers.com/trace/crash.tar.xz
> >>>>>>>>>>>>
> >>>>>>>>>>>> Thanks,
> >>>>>>>>>>>> Robert
> >>>>>>>>>>>> ----------------
> >>>>>>>>>>>> Robert LeBlanc
> >>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62
> >>>>>>>>>>>> B9F1
> >>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>> On Fri, Nov 4, 2016 at 3:57 PM, Robert LeBlanc
> >>>>>>>>>>>> <robert@leblancnet.us> wrote:
> >>>>>>>>>>>>> We hit this yesterday, this time it was on the tx thread (the
> >>>>>>>>>>>>> other
> >>>>>>>>>>>>> ones before seem to be on the rx thread). We weren't able to
> >>>>>>>>>>>>> get a
> >>>>>>>>>>>>> kernel dump on this. We'll try to get one next time.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> # ps axuw | grep "D.*iscs[i]"
> >>>>>>>>>>>>> root     12383  0.0  0.0      0     0 ?        D    Nov03
> >>>>>>>>>>>>> 0:04 [iscsi_np]
> >>>>>>>>>>>>> root     23016  0.0  0.0      0     0 ?        D    Nov03
> >>>>>>>>>>>>> 0:00 [iscsi_ttx]
> >>>>>>>>>>>>> root     23018  0.0  0.0      0     0 ?        D    Nov03
> >>>>>>>>>>>>> 0:00 [iscsi_ttx]
> >>>>>>>>>>>>> # cat /proc/12383/stack
> >>>>>>>>>>>>> [<ffffffff814f24af>] iscsit_stop_session+0x19f/0x1d0
> >>>>>>>>>>>>> [<ffffffff814e3c66>]
> >>>>>>>>>>>>> iscsi_check_for_session_reinstatement+0x1e6/0x270
> >>>>>>>>>>>>> [<ffffffff814e6620>]
> >>>>>>>>>>>>> iscsi_target_check_for_existing_instances+0x30/0x40
> >>>>>>>>>>>>> [<ffffffff814e6770>] iscsi_target_do_login+0x140/0x640
> >>>>>>>>>>>>> [<ffffffff814e7b0c>] iscsi_target_start_negotiation+0x1c/0xb0
> >>>>>>>>>>>>> [<ffffffff814e585b>] iscsi_target_login_thread+0xa9b/0xfc0
> >>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
> >>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
> >>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
> >>>>>>>>>>>>> # cat /proc/23016/stack
> >>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
> >>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
> >>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
> >>>>>>>>>>>>> [<ffffffff814e110f>]
> >>>>>>>>>>>>> iscsit_take_action_for_connection_exit+0x7f/0x100
> >>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
> >>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
> >>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
> >>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
> >>>>>>>>>>>>> # cat /proc/23018/stack
> >>>>>>>>>>>>> [<ffffffff814ce0d9>] target_wait_for_sess_cmds+0x49/0x1a0
> >>>>>>>>>>>>> [<ffffffffa058b92b>] isert_wait_conn+0x1ab/0x2f0 [ib_isert]
> >>>>>>>>>>>>> [<ffffffff814f2642>] iscsit_close_connection+0x162/0x870
> >>>>>>>>>>>>> [<ffffffff814e110f>]
> >>>>>>>>>>>>> iscsit_take_action_for_connection_exit+0x7f/0x100
> >>>>>>>>>>>>> [<ffffffff814f122a>] iscsi_target_tx_thread+0x1aa/0x1d0
> >>>>>>>>>>>>> [<ffffffff8109d7c8>] kthread+0xd8/0xf0
> >>>>>>>>>>>>> [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
> >>>>>>>>>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> From dmesg:
> >>>>>>>>>>>>> [  394.476332] INFO: rcu_sched self-detected stall on CPU
> >>>>>>>>>>>>> [  394.476334]  20-...: (23976 ticks this GP)
> >>>>>>>>>>>>> idle=edd/140000000000001/0 softirq=292/292 fqs=18788
> >>>>>>>>>>>>> [  394.476336]   (t=24003 jiffies g=3146 c=3145 q=0)
> >>>>>>>>>>>>> [  394.476337] Task dump for CPU 20:
> >>>>>>>>>>>>> [  394.476338] kworker/u68:2   R  running task        0 12906
> >>>>>>>>>>>>> 2 0x00000008
> >>>>>>>>>>>>> [  394.476345] Workqueue: isert_comp_wq isert_cq_work
> >>>>>>>>>>>>> [ib_isert]
> >>>>>>>>>>>>> [  394.476346]  ffff883f2fe38000 00000000f805705e
> >>>>>>>>>>>>> ffff883f7fd03da8
> >>>>>>>>>>>>> ffffffff810ac8ff
> >>>>>>>>>>>>> [  394.476347]  0000000000000014 ffffffff81adb680
> >>>>>>>>>>>>> ffff883f7fd03dc0
> >>>>>>>>>>>>> ffffffff810af239
> >>>>>>>>>>>>> [  394.476348]  0000000000000015 ffff883f7fd03df0
> >>>>>>>>>>>>> ffffffff810e1cd0
> >>>>>>>>>>>>> ffff883f7fd17b80
> >>>>>>>>>>>>> [  394.476348] Call Trace:
> >>>>>>>>>>>>> [  394.476354]  <IRQ>  [<ffffffff810ac8ff>]
> >>>>>>>>>>>>> sched_show_task+0xaf/0x110
> >>>>>>>>>>>>> [  394.476355]  [<ffffffff810af239>] dump_cpu_task+0x39/0x40
> >>>>>>>>>>>>> [  394.476357]  [<ffffffff810e1cd0>]
> >>>>>>>>>>>>> rcu_dump_cpu_stacks+0x80/0xb0
> >>>>>>>>>>>>> [  394.476359]  [<ffffffff810e6100>]
> >>>>>>>>>>>>> rcu_check_callbacks+0x540/0x820
> >>>>>>>>>>>>> [  394.476360]  [<ffffffff810afe11>] ?
> >>>>>>>>>>>>> account_system_time+0x81/0x110
> >>>>>>>>>>>>> [  394.476363]  [<ffffffff810faa60>] ?
> >>>>>>>>>>>>> tick_sched_do_timer+0x50/0x50
> >>>>>>>>>>>>> [  394.476364]  [<ffffffff810eb599>]
> >>>>>>>>>>>>> update_process_times+0x39/0x60
> >>>>>>>>>>>>> [  394.476365]  [<ffffffff810fa815>]
> >>>>>>>>>>>>> tick_sched_handle.isra.17+0x25/0x60
> >>>>>>>>>>>>> [  394.476366]  [<ffffffff810faa9d>] tick_sched_timer+0x3d/0x70
> >>>>>>>>>>>>> [  394.476368]  [<ffffffff810ec182>]
> >>>>>>>>>>>>> __hrtimer_run_queues+0x102/0x290
> >>>>>>>>>>>>> [  394.476369]  [<ffffffff810ec668>]
> >>>>>>>>>>>>> hrtimer_interrupt+0xa8/0x1a0
> >>>>>>>>>>>>> [  394.476372]  [<ffffffff81052c65>]
> >>>>>>>>>>>>> local_apic_timer_interrupt+0x35/0x60
> >>>>>>>>>>>>> [  394.476374]  [<ffffffff8172423d>]
> >>>>>>>>>>>>> smp_apic_timer_interrupt+0x3d/0x50
> >>>>>>>>>>>>> [  394.476376]  [<ffffffff817224f7>]
> >>>>>>>>>>>>> apic_timer_interrupt+0x87/0x90
> >>>>>>>>>>>>> [  394.476379]  <EOI>  [<ffffffff810d71be>] ?
> >>>>>>>>>>>>> console_unlock+0x41e/0x4e0
> >>>>>>>>>>>>> [  394.476380]  [<ffffffff810d757c>] vprintk_emit+0x2fc/0x500
> >>>>>>>>>>>>> [  394.476382]  [<ffffffff810d78ff>] vprintk_default+0x1f/0x30
> >>>>>>>>>>>>> [  394.476384]  [<ffffffff81174dde>] printk+0x5d/0x74
> >>>>>>>>>>>>> [  394.476388]  [<ffffffff814bce21>]
> >>>>>>>>>>>>> transport_lookup_cmd_lun+0x1d1/0x200
> >>>>>>>>>>>>> [  394.476390]  [<ffffffff814ee8c0>]
> >>>>>>>>>>>>> iscsit_setup_scsi_cmd+0x230/0x540
> >>>>>>>>>>>>> [  394.476392]  [<ffffffffa058dbf3>]
> >>>>>>>>>>>>> isert_rx_do_work+0x3f3/0x7f0 [ib_isert]
> >>>>>>>>>>>>> [  394.476394]  [<ffffffffa058e174>] isert_cq_work+0x184/0x770
> >>>>>>>>>>>>> [ib_isert]
> >>>>>>>>>>>>> [  394.476396]  [<ffffffff8109740f>]
> >>>>>>>>>>>>> process_one_work+0x14f/0x400
> >>>>>>>>>>>>> [  394.476397]  [<ffffffff81097c84>] worker_thread+0x114/0x470
> >>>>>>>>>>>>> [  394.476398]  [<ffffffff8171d32a>] ? __schedule+0x34a/0x7f0
> >>>>>>>>>>>>> [  394.476399]  [<ffffffff81097b70>] ?
> >>>>>>>>>>>>> rescuer_thread+0x310/0x310
> >>>>>>>>>>>>> [  394.476400]  [<ffffffff8109d7c8>] kthread+0xd8/0xf0
> >>>>>>>>>>>>> [  394.476402]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
> >>>>>>>>>>>>> [  394.476403]  [<ffffffff81721a8f>] ret_from_fork+0x3f/0x70
> >>>>>>>>>>>>> [  394.476404]  [<ffffffff8109d6f0>] ? kthread_park+0x60/0x60
> >>>>>>>>>>>>> [  405.716632] Unexpected ret: -104 send data 360
> >>>>>>>>>>>>> [  405.721711] tx_data returned -32, expecting 360.
> >>>>>>>>>>>>> ----------------
> >>>>>>>>>>>>> Robert LeBlanc
> >>>>>>>>>>>>> PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62
> >>>>>>>>>>>>> B9F1
> >>>>>>>>>
> >>>>>>>>> When you combine this trace with the newest one, it really makes me
> >>>>>>>>> thing there is something of a bad interaction between the new drain
> >>>>>>>>> cq
> >>>>>>>>> API and the iser/isert implementation to use said API.  Sagi,
> >>>>>>>>> Christoph?
> >>>>>>>>>
> >>>>>>>>> --
> >>>>>>>>> Doug Ledford <dledford@redhat.com>
> >>>>>>>>>     GPG Key ID: B826A3330E572FDD
> >>>>>>>>>     Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57
> >>>>>>>>>     2FDD
> >>>>>>>>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Hello Robert

I am going to have some time next week to set this up and see if I can help troubleshoot at all
Can you share a summary (direct email to me) of your latest tested configuration and module parameters in use that is still failing.
I looked back in the notes, can you confirm that with back-to-back direct connect the issue does not happen.

I have a setup with 2 MLX4 cards, so the intention is to use 1 as the server and 1 as the client. 
I have a FDR switch is will use between them.

Thanks
Laurence
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Robert LeBlanc Jan. 6, 2017, 7:12 p.m. UTC | #3
Laurence,

Since the summary may be helpful to others, I'm just going to send it
to the list.

I've been able to reproduce the D state problem on both Infiniband and
RoCE, but it is much easier to reproduce on RoCE due to another bug
and doesn't require being at the server to yank the cable (remote
power control of a switch may work as well). The bug seems to be
triggered by an abrupt and unexpected break in communications

Common config between both Infiniband and RoCE:
====
* Linux kernel 4.9 (using only inbox drivers, no OFED)
* Target and initiator both configured on the same subnet
* 100 GB ram disk exported by iser [1]
* Iser volume imported on client and the whole block device formatted ext4.
* FIO run on iser volume on the client [2]
* Anything not mentioned in this document should be default (it is a
pretty simple config)

Infiniband specific config:
====
* Any IB cards should work (my config has ConnectX-3, but has also
been seen on Connect-IB in our environment)
* Back to back (my config) or connected to a switch
* OpenSM running on the target (my config), or on a separate host (not
sure how cutting power to the switch may impact triggering the bug, I
believe it will still trigger ok)
* While running the fio job, pull the cable on the initiator side.
After about 120 seconds the fio job will fail and the iscsi processes
should be in D state on the target.

RoCE specific config:
====
* Only tested with ConnectX-4-LX cards (I don't know if others will
trigger the problem, pulling the cable like in the Infiniband section,
may also trigger the bug if it doesn't trigger automatically)
* Hosts must be connected by a switch or a Linux bridge that doesn't
have RoCE offload. I was able to trigger the bugs with a back to back
connection if the target clamps the speed to 10 Gb [3].
* Running the fio job should be enough to trigger the RoCE card to
unexpectedly drop the RDMA connection and that should then cause the
target iscsci processes to go into D state.

For either the Infiniband or RoCE setup, the bug can be triggered with
only two hosts connected back to back. If something is still not
clear, please let me know.

[1] /etc/saveconfig.json
```json
{
  "fabric_modules": [],
  "storage_objects": [
    {
      "attributes": {
        "block_size": 512,
        "emulate_3pc": 1,
        "emulate_caw": 1,
        "emulate_dpo": 0,
        "emulate_fua_read": 0,
        "emulate_fua_write": 1,
        "emulate_model_alias": 1,
        "emulate_rest_reord": 0,
        "emulate_tas": 1,
        "emulate_tpu": 0,
        "emulate_tpws": 0,
        "emulate_ua_intlck_ctrl": 0,
        "emulate_write_cache": 0,
        "enforce_pr_isids": 1,
        "force_pr_aptpl": 0,
        "is_nonrot": 1,
        "max_unmap_block_desc_count": 0,
        "max_unmap_lba_count": 0,
        "max_write_same_len": 0,
        "optimal_sectors": 4294967288,
        "pi_prot_format": 0,
        "pi_prot_type": 0,
        "queue_depth": 128,
        "unmap_granularity": 0,
        "unmap_granularity_alignment": 0
      },
      "name": "test1",
      "plugin": "ramdisk",
      "size": 107374182400,
      "wwn": "7486ed41-585e-400f-8799-ac605485b221"
    }
  ],
  "targets": [
    {
      "fabric": "iscsi",
      "tpgs": [
        {
          "attributes": {
            "authentication": 0,
            "cache_dynamic_acls": 1,
            "default_cmdsn_depth": 64,
            "default_erl": 0,
            "demo_mode_discovery": 1,
            "demo_mode_write_protect": 0,
            "generate_node_acls": 1,
            "login_timeout": 15,
            "netif_timeout": 2,
            "prod_mode_write_protect": 0,
            "t10_pi": 0
          },
          "enable": true,
          "luns": [
            {
              "index": 0,
              "storage_object": "/backstores/ramdisk/test1"
            }
          ],
          "node_acls": [],
          "parameters": {
            "AuthMethod": "CHAP,None",
            "DataDigest": "CRC32C,None",
            "DataPDUInOrder": "Yes",
            "DataSequenceInOrder": "Yes",
            "DefaultTime2Retain": "20",
            "DefaultTime2Wait": "2",
            "ErrorRecoveryLevel": "0",
            "FirstBurstLength": "65536",
            "HeaderDigest": "CRC32C,None",
            "IFMarkInt": "Reject",
            "IFMarker": "No",
            "ImmediateData": "Yes",
            "InitialR2T": "Yes",
            "MaxBurstLength": "262144",
            "MaxConnections": "1",
            "MaxOutstandingR2T": "1",
            "MaxRecvDataSegmentLength": "8192",
            "MaxXmitDataSegmentLength": "262144",
            "OFMarkInt": "Reject",
            "OFMarker": "No",
            "TargetAlias": "LIO Target"
          },
          "portals": [
            {
              "ip_address": "0.0.0.0",
              "iser": true,
              "port": 3260
            }
          ],
          "tag": 1
        }
      ],
      "wwn": "iqn.2016-12.com.betterservers"
    }
  ]
}
```
[2] echo "3" > /proc/sys/vm/drop_caches; fio --rw=read --bs=4K
--size=1G --numjobs=40 --name=worker.matt --group_reporting
[3] ethtool -s eth3 speed 10000 advertise 0x80000
----------------
Robert LeBlanc
PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
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diff mbox

Patch

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
b/drivers/infiniband/ulp/isert/ib_isert.c
index 6dd43f6..1e53502 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2595,7 +2595,7 @@  static void isert_wait_conn(struct iscsi_conn *conn)
       isert_conn_terminate(isert_conn);
       mutex_unlock(&isert_conn->mutex);

-       ib_drain_qp(isert_conn->qp);
+       ib_close_qp(isert_conn->qp);
       isert_put_unsol_pending_cmds(conn);
       isert_wait4cmds(conn);
       isert_wait4logout(isert_conn);