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 >
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