Re: [PATCH v2 0/5] nvme-fc: Fix blktests hangers

[Ewan Milne]

We ran this patch series through our regression and NVMe/FC boot from SAN tests.
(I think 4/5 will also resolve some instability / race condition with
kickstart, since the connect
is now synchronous, but we may need some more time to full validate
that.  I was going
to pursue a userspace solution but this may be good enough.)

Notwithstanding the other comments re: error codes, etc. feel free to add:

Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
Tested-by: Marco Patalano (mpatalan@xxxxxxxxxx>

On Tue, Jun 20, 2023 at 9:39 AM Daniel Wagner <dwagner@xxxxxxx> wrote:
>
> With the additinal 3 patches and the blktests changes [1] I am able to run the
> tests in a loop for a while without failures. I expect there are more problems
> hidden but with these changes the first milesone is reached.
>
> The first new patch is actually one from a previous attempt. It addresses the
> problem in unloading path where we dont make any progress more [2].
>
> The next two patches change the existing initial connection attempt of FC to
> a synchronous one. Without this the auth test fail [3].
>
> Daniel
>
>
> [1] https://lore.kernel.org/linux-nvme/20230620132703.20648-1-dwagner@xxxxxxx/
> [2] https://lore.kernel.org/linux-nvme/20230418130159.11075-1-dwagner@xxxxxxx/
> [3] https://lore.kernel.org/linux-nvme/j4w7724skjsapgtp6wtll5fgsb4adhpfdtrif52lhc7iql4inf@3mu2gbjrrtcs/
>
> changes:
>
> v2:
>   - added RBs
>   - added new patches
>
> v1:
>   - https://lore.kernel.org/linux-nvme/20230615094356.14878-1-dwagner@xxxxxxx/
>
>
> Initial cover letter:
>
> A couple more fixes to enable blktests for the fc transport.
>
> 1) Another module unloading hanger which can be triggered with
>    the nvme/048 tests:
>
>    run blktests nvme/048 at 2023-06-06 13:04:49
>    nvmet: adding nsid 1 to subsystem blktests-subsystem-1
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "blktests-subsystem-1"
>    (NULL device *): {0:0} Association created
>    [478] nvmet: ctrl 1 start keep-alive timer for 1 secs
>    [478] nvmet: check nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a
>    [478] nvmet: nvmet_setup_dhgroup: ctrl 1 selecting dhgroup 0
>    [478] nvmet: No authentication provided
>    nvmet: creating nvm controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a.
>    [478] nvmet: adding queue 1 to ctrl 1.
>    [407] nvmet: adding queue 2 to ctrl 1.
>    [6549] nvmet: adding queue 3 to ctrl 1.
>    [1760] nvmet: adding queue 4 to ctrl 1.
>    nvme nvme2: NVME-FC{0}: controller connect complete
>    nvme nvme2: NVME-FC{0}: new ctrl: NQN "blktests-subsystem-1"
>    [478] nvmet: ctrl 1 reschedule traffic based keep-alive timer
>    [407] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    nvme nvme2: NVME-FC{0}: io failed due to lldd error 6
>    nvme nvme2: NVME-FC{0}: transport association event: transport detected io error
>    nvme nvme2: NVME-FC{0}: resetting controller
>    [478] nvmet: ctrl 1 stop keep-alive
>    (NULL device *): {0:0} Association deleted
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "blktests-subsystem-1"
>    (NULL device *): {0:0} Association freed
>    (NULL device *): {0:0} Association created
>    (NULL device *): Disconnect LS failed: No Association
>    [407] nvmet: ctrl 1 start keep-alive timer for 1 secs
>    [407] nvmet: check nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a
>    [407] nvmet: nvmet_setup_dhgroup: ctrl 1 selecting dhgroup 0
>    [407] nvmet: No authentication provided
>    nvmet: creating nvm controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a.
>    nvme nvme2: reconnect: revising io queue count from 4 to 1
>    [478] nvmet: adding queue 1 to ctrl 1.
>    nvme nvme2: NVME-FC{0}: controller connect complete
>    [478] nvmet: ctrl 1 reschedule traffic based keep-alive timer
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [407] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    nvme nvme2: NVME-FC{0}: io failed due to lldd error 6
>    nvme nvme2: NVME-FC{0}: transport association event: transport detected io error
>    nvme nvme2: NVME-FC{0}: resetting controller
>    [478] nvmet: ctrl 1 stop keep-alive
>    (NULL device *): {0:0} Association deleted
>    (NULL device *): {0:0} Association freed
>    (NULL device *): Disconnect LS failed: No Association
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "blktests-subsystem-1"
>    (NULL device *): {0:0} Association created
>    [1760] nvmet: ctrl 1 start keep-alive timer for 1 secs
>    [1760] nvmet: check nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a
>    [1760] nvmet: nvmet_setup_dhgroup: ctrl 1 selecting dhgroup 0
>    [1760] nvmet: No authentication provided
>    nvmet: creating nvm controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:3d0c3f5d-cb37-4bc4-af29-2168953bfc0a.
>    nvme nvme2: reconnect: revising io queue count from 1 to 4
>    [478] nvmet: adding queue 1 to ctrl 1.
>    [407] nvmet: adding queue 2 to ctrl 1.
>    [6549] nvmet: adding queue 3 to ctrl 1.
>    [1760] nvmet: adding queue 4 to ctrl 1.
>    nvme nvme2: NVME-FC{0}: controller connect complete
>    [1760] nvmet: ctrl 1 reschedule traffic based keep-alive timer
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [478] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [1760] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    [6549] nvmet: ctrl 1 update keep-alive timer for 1 secs
>    nvme nvme2: Removing ctrl: NQN "blktests-subsystem-1"
>    [407] nvmet: ctrl 1 stop keep-alive
>    (NULL device *): {0:0} Association deleted
>    (NULL device *): {0:0} Association freed
>    (NULL device *): Disconnect LS failed: No Association
>    nvme_fc: nvme_fc_exit_module: waiting for ctlr deletes
>    BTRFS info (device vda2): qgroup scan completed (inconsistency flag cleared)
>    INFO: task modprobe:11758 blocked for more than 491 seconds.
>          Tainted: G        W          6.4.0-rc2+ #3
>    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>    task:modprobe        state:D stack:0     pid:11758 ppid:11585  flags:0x00004002
>    Call Trace:
>     <TASK>
>     __schedule+0x17b5/0x4870
>     ? finish_lock_switch+0x8f/0x120
>     ? finish_task_switch+0x17f/0x5c0
>     ? __sched_text_start+0x10/0x10
>     ? __schedule+0x17bd/0x4870
>     ? do_raw_spin_trylock+0xc9/0x1f0
>     schedule+0xe6/0x1e0
>     schedule_timeout+0x7e/0x1e0
>     ? __cfi_schedule_timeout+0x10/0x10
>     ? do_raw_spin_trylock+0xc9/0x1f0
>     ? __cfi_lock_release+0x10/0x10
>     ? do_raw_spin_unlock+0x116/0x8a0
>     wait_for_common+0x377/0x600
>     ? wait_for_completion+0x30/0x30
>     cleanup_module+0x222/0x240 [nvme_fc bda1ef6f83d00208ba257c5d0ac34dd6bdb58bf9]
>     __se_sys_delete_module+0x388/0x550
>     ? __x64_sys_delete_module+0x50/0x50
>     ? task_work_run+0x236/0x290
>     ? syscall_enter_from_user_mode+0x2e/0x210
>     do_syscall_64+0x6e/0xa0
>     ? syscall_exit_to_user_mode+0x5e/0x220
>     ? do_syscall_64+0x7d/0xa0
>     ? syscall_exit_to_user_mode+0x5e/0x220
>     ? do_syscall_64+0x7d/0xa0
>     ? syscall_exit_to_user_mode+0x5e/0x220
>     ? do_syscall_64+0x7d/0xa0
>     entry_SYSCALL_64_after_hwframe+0x72/0xdc
>    RIP: 0033:0x7fa80811aebb
>    RSP: 002b:00007fff80ea0a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
>    RAX: ffffffffffffffda RBX: 000055a0b5acf1f0 RCX: 00007fa80811aebb
>    RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055a0b5acf258
>    RBP: 0000000000000000 R08: 1999999999999999 R09: 0000000000000000
>    R10: 00007fa808193ac0 R11: 0000000000000206 R12: 00007fff80ea0ad0
>    R13: 000055a0b5acf1f0 R14: 0000000000000000 R15: 0000000000000000
>     </TASK>
>
>
> 2) When executing blktests nvme/030 in a tight loop, I was able to
>    reproduce a different hanger. In this case the ->done() function
>    was never executed on the host fc side. It turns out we didn't
>    enqueue work items correctly and thus would only process one
>    work item.
>
>    run blktests nvme/030 at 2023-06-13 14:03:52
>    nvmet: adding nsid 1 to subsystem blktests-subsystem-1
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    (NULL device *): {0:0} Association created
>    [23733] nvmet: ctrl 1 start keep-alive timer for 120 secs
>    nvmet: creating discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:242d4a24-2484-4a80-8234-d0169409c5e8.
>    nvme nvme2: NVME-FC{0}: controller connect complete
>    nvme nvme2: NVME-FC{0}: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    nvme nvme2: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    [23771] nvmet: ctrl 1 stop keep-alive
>    nvmet: adding nsid 1 to subsystem blktests-subsystem-2
>    (NULL device *): {0:0} Association deleted
>    (NULL device *): {0:0} Association freed
>    (NULL device *): Disconnect LS failed: No Association
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    (NULL device *): {0:0} Association created
>    [27320] nvmet: ctrl 1 start keep-alive timer for 120 secs
>    nvmet: creating discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:242d4a24-2484-4a80-8234-d0169409c5e8.
>    nvme nvme2: NVME-FC{0}: controller connect complete
>    nvme nvme2: NVME-FC{0}: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    nvme nvme2: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    [27320] nvmet: ctrl 1 stop keep-alive
>    nvme nvme2: NVME-FC{0}: create association : host wwpn 0x20001100aa000002  rport wwpn 0x20001100aa000001: NQN "nqn.2014-08.org.nvmexpress.discovery"
>    (NULL device *): {0:1} Association created
>    (NULL device *): {0:0} Association deleted
>    (NULL device *): {0:0} Association freed
>    (NULL device *): Disconnect LS failed: No Association
>    INFO: task kworker/u8:4:102 blocked for more than 491 seconds.
>          Tainted: G        W          6.4.0-rc2+ #3
>    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>    task:kworker/u8:4    state:D stack:0     pid:102   ppid:2      flags:0x00004000
>    Workqueue: nvme-wq nvme_fc_connect_ctrl_work [nvme_fc]
>    Call Trace:
>     <TASK>
>     __schedule+0x17b5/0x4870
>     ? try_to_wake_up+0xb5/0xfc0
>     ? __cfi_lock_release+0x10/0x10
>     ? __sched_text_start+0x10/0x10
>     ? _raw_spin_unlock_irqrestore+0x24/0x50
>     ? lock_release+0x2aa/0xd10
>     ? wq_worker_sleeping+0x1e/0x200
>     schedule+0xe6/0x1e0
>     schedule_timeout+0x7e/0x1e0
>     ? __cfi_schedule_timeout+0x10/0x10
>     ? mark_lock+0x94/0x340
>     ? lockdep_hardirqs_on_prepare+0x2aa/0x5e0
>     wait_for_common+0x377/0x600
>     ? queue_work_on+0x57/0xa0
>     ? wait_for_completion+0x30/0x30
>     nvme_fc_connect_ctrl_work+0x7dc/0x1a80 [nvme_fc 39e2bf78272df3a610fb1f9884513e99038af746]
>     process_one_work+0x80f/0xfb0
>     ? rescuer_thread+0x1130/0x1130
>     ? do_raw_spin_trylock+0xc9/0x1f0
>     ? lock_acquired+0x310/0x9a0
>     ? worker_thread+0xd5e/0x1260
>     worker_thread+0xbde/0x1260
>     kthread+0x25d/0x2f0
>     ? __cfi_worker_thread+0x10/0x10
>     ? __cfi_kthread+0x10/0x10
>     ret_from_fork+0x29/0x50
>     </TASK>
>
> Daniel Wagner (5):
>   nvme-fc: Do not wait in vain when unloading module
>   nvme-fcloop: queue work items correctly
>   nvmet-fcloop: Remove remote port from list when unlinking
>   nvme-fc: Make initial connect attempt synchronous
>   nvme-fc: do no free ctrl opts
>
>  drivers/nvme/host/fc.c       | 43 ++++++++++++++++++------------------
>  drivers/nvme/target/fcloop.c | 15 +++++--------
>  2 files changed, 27 insertions(+), 31 deletions(-)
>
> --
> 2.41.0
>
>