On Fri, Feb 12, 2016 at 12:30 AM, Himanshu Madhani
<himanshu.madh...@qlogic.com> wrote:
> Hi Nic,
>
>
>
> On 2/11/16, 3:47 PM, "Nicholas A. Bellinger" <n...@linux-iscsi.org> wrote:
>
>>On Wed, 2016-02-10 at 22:53 -0800, Nicholas A. Bellinger wrote:
>>> On Tue, 2016-02-09 at 18:03 +0000, Himanshu Madhani wrote:
>>> > On 2/8/16, 9:25 PM, "Nicholas A. Bellinger" <n...@linux-iscsi.org>
>>>wrote:
>>> > >On Mon, 2016-02-08 at 23:27 +0000, Himanshu Madhani wrote:
>>> > >>
>>> > >> I am testing this series with with 4.5.0-rc2+ kernel and I am
>>>seeing
>>> > >>issue
>>> > >> where trying to trigger
>>> > >> sg_reset with option of host/device/bus in loop at 120second
>>>interval
>>> > >> causes call stack. At this point
>>> > >> removing configuration hangs indefinitely. See attached dmesg
>>>output
>>> > >>from
>>> > >> my setup.
>>> > >>
>>> > >
>>> > >Thanks alot for testing this.
>>> > >
>>> > >So It looks like we're still hitting a indefinite schedule() on
>>> > >se_cmd->cmd_wait_comp once tcm_qla2xxx session disconnect/reconnect
>>> > >occurs, after repeated explicit active I/O remote-port sg_resets.
>>> > >
>>> > >Does this trigger on the first tcm_qla2xxx session reconnect after
>>> > >explicit remote-port sg_reset..?  Are session reconnects actively
>>>being
>>> > >triggered during the test..?
>>> > >
>>> > >To verify the latter for iscsi-target, I've been using a small patch
>>>to
>>> > >trigger session reset from TMR kthread context in order to simulate
>>>the
>>> > >I_T disconnects.  Something like that would be useful for verifying
>>>with
>>> > >tcm_qla2xxx too.
>>> > >
>>> > >That said, I'll be reproducing with tcm_qla2xxx ports this week, and
>>> > >will enable various debug in a WIP branch for testing.
>>>
>>> Following up here..
>>>
>>> So far using my test setup with ISP2532 ports in P2P + RAMDISK_MCP and
>>> v4.5-rc1, repeated remote-port active I/O LUN_RESET (sg_reset -d) has
>>> been functioning as expected with a blocksize_range=4k-256k + iodepth=32
>>> fio write-verify style workload.
>>>
>>> No ->cmd_kref -1 OOPsen or qla2xxx initiator generated ABORT_TASKs from
>>> outstanding target TAS responses, nor fio write-verify failures to
>>> report after 800x remote-port active I/O LUN_RESETS.
>>>
>>> Next step will be to verify explicit tcm_qla2xxx port + module shutdown
>>> after 1K test iterations, and then IBLOCK async completions <-> NVMe
>>> backends with the same case.
>>>
>>
>>After letting this test run over-night up to 7k active I/O remote-port
>>LUN_RESETs, things are still functioning as expected.
>>
>>Also, /etc/init.d/target stop was able to successfully shutdown all
>>active sessions and unload tcm_qla2xxx after the test run.
>>
>>So AFAICT, the active I/O remote-port LUN_RESET changes are stable with
>>tcm_qla2xxx ports, separate from concurrent session disconnect hung task
>>you reported earlier.
>>
>>That said, I'll likely push this series as-is for -rc4, given that Dan
>>has also been able to verify the non conncurrent session disconnect case
>>on his setup generating constant ABORT_TASKs, and it's still surviving
>>both cases for iscsi-target ports.
>>
>>Please give the debug patch from last night a shot, and see if we can
>>determine the se_cmd states when you hit the hung task.
>
> I¹ll give your latest debug patch try in a little while
>
> From the testing that I have done, what is seen is that active IO has
> already been completed and qla2xxx driver is waiting for commands to be
> Completed and it¹s waiting indefinitely for cmd_wait_comp.
> So it looks like there is a missing complete call from target_core. I¹ve
> attached our analysis from crash debug on a live system after the issues
> happens.
>
>
> I can recreate this issue at will within 5 minute of triggering sg_reset
> with following steps
>
> 1. Export 4 RAM disk LUNs on each of 2 port adapter. Initiator will see 8
> RAM disk targets
> 2. Start IO with 4K block size and 8 threads with 80% write 20% read and
> 100% dandom.
> (I am using vdbench for generating IO. I can provide setup/config script
> if needed)
> 3. Start sg_reset for each LUNs with first device, bus and host with 120s
> delay. (I¹ve attached
> My script that I am using for triggering sg_reset)
>
>>
>>Thank you,
>>
>>-nab
>>
>

Has there been any update to this?

Thanks
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