nvme_tcp: nvme connect failed after execute stress-ng: unshare

[Yi Zhang]

Hello

Recently I found nvme-tcp connecting always failed[1] after execute stress-ng:unshare[2], by bisecting I finally found it was introduced with commit[3], the connecting works well after revert it.
I'm not sure whether it's one test case issue or kernel issue, could anyone help check it.

[1]
# sh test.sh 
+ ./stress-ng/stress-ng --unshare 0 --timeout 5 --log-file unshare.log
stress-ng: info:  [355534] dispatching hogs: 32 unshare
stress-ng: info:  [355534] successful run completed in 5.04s
+ modprobe null-blk nr-devices=1
+ modprobe nvmet-tcp
+ modprobe nvme-tcp
+ nvmetcli restore tcp.json
+ nvme connect -t tcp -n nqn.2014-08.org.nvmexpress.discovery -a 127.0.0.1 -s 4420
Failed to write to /dev/nvme-fabrics: Input/output error

# dmesg | tail -9
[  700.012299] null_blk: module loaded
[  700.073415] nvmet: adding nsid 1 to subsystem blktests-subsystem-1
[  700.073923] nvmet_tcp: enabling port 0 (127.0.0.1:4420)
[  715.291020] nvmet: ctrl 1 keep-alive timer (15 seconds) expired!
[  715.297031] nvmet: ctrl 1 fatal error occurred!
[  749.939898] nvmet: creating controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:e405e6bb-8e28-4a73-b338-3fddb5746b8c.
[  763.417376] nvme nvme0: queue 0: timeout request 0x0 type 4
[  763.422979] nvme nvme0: Connect command failed, error wo/DNR bit: 881
[  763.429419] nvme nvme0: failed to connect queue: 0 ret=881

# uname -r
5.9.0-rc4


[2] stress-ng: unshare case
https://github.com/ColinIanKing/stress-ng.git
https://github.com/ColinIanKing/stress-ng/blob/master/stress-unshare.c


[3] 
commit e1eb26fa62d04ec0955432be1aa8722a97cb52e7
Author: Giuseppe Scrivano <gscrivan at redhat.com>
Date:   Sun Jun 7 21:40:10 2020 -0700

    ipc/namespace.c: use a work queue to free_ipc
    
    the reason is to avoid a delay caused by the synchronize_rcu() call in
    kern_umount() when the mqueue mount is freed.


[4]
# cat tcp.json 
{
  "hosts": [],
  "ports": [
    {
      "addr": {
        "adrfam": "ipv4",
        "traddr": "127.0.0.1",
        "treq": "not specified",
        "trsvcid": "4420",
        "trtype": "tcp"
      },
      "portid": 0,
      "referrals": [],
      "subsystems": [
        "blktests-subsystem-1"
      ]
    }
  ],
  "subsystems": [
    {
      "allowed_hosts": [],
      "attr": {
        "allow_any_host": "1",
        "cntlid_max": "65519",
        "cntlid_min": "1",
        "model": "Linux",
        "pi_enable": "0",
        "serial": "7d833f5501f6b240",
        "version": "1.3"
      },
      "namespaces": [
        {
          "device": {
            "nguid": "00000000-0000-0000-0000-000000000000",
            "path": "/dev/nullb0",
            "uuid": "b07c7eef-8428-47bf-8e79-26ec8c30f334"
          },
          "enable": 1,
          "nsid": 1
        }
      ],
      "nqn": "blktests-subsystem-1"
    }
  ]
}


Best Regards,
  Yi Zhang