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 <rob...@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 <rob...@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 <rob...@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 <rob...@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 <rob...@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 <dledf...@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 <rob...@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 <rob...@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 <rob...@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 <dledf...@redhat.com>
>>>>>> GPG Key ID: B826A3330E572FDD
>>>>>> Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD
>>>>>>
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