The WARNING[1] was fixed by ming's patch[2], but the timeout issue still exists, so file this issue to track it. [1] refcount_t: underflow; use-after-free https://marc.info/?l=linux-block&m=160215221708632&w=2 [2] https://marc.info/?l=linux-block&m=160285851624680&w=2 Reproduce steps: cd /root/blktests; nvme_trtype=tcp ./check nvme/012 ENV: # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian Address sizes: 48 bits physical, 48 bits virtual CPU(s): 12 On-line CPU(s) list: 0-11 Thread(s) per core: 1 Core(s) per socket: 6 Socket(s): 2 NUMA node(s): 2 Vendor ID: AuthenticAMD CPU family: 16 Model: 8 Model name: Six-Core AMD Opteron(tm) Processor 2427 Stepping: 0 CPU MHz: 800.000 CPU max MHz: 2200.0000 CPU min MHz: 800.0000 BogoMIPS: 4399.80 Virtualization: AMD-V L1d cache: 768 KiB L1i cache: 768 KiB L2 cache: 6 MiB L3 cache: 12 MiB NUMA node0 CPU(s): 0,2,4,6,8,10 NUMA node1 CPU(s): 1,3,5,7,9,11 Vulnerability Itlb multihit: Not affected Vulnerability L1tf: Not affected Vulnerability Mds: Not affected Vulnerability Meltdown: Not affected Vulnerability Spec store bypass: Not affected Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Vulnerability Spectre v2: Mitigation; Full AMD retpoline, STIBP disabled, RSB filling Vulnerability Srbds: Not affected Vulnerability Tsx async abort: Not affected Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl non stop_tsc cpuid extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt hw_pstate vmmcall npt lbrv svm_lock nrip_s ave pausefilter # free total used free shared buff/cache available Mem: 4028996 182088 3367340 972 479568 3569996 Swap: 4156412 0 4156412 dmesg: [32808.189629] run blktests nvme/012 at 2020-10-19 06:57:14 [32808.282069] nvmet: adding nsid 1 to subsystem blktests-subsystem-1 [32808.301481] nvmet_tcp: enabling port 0 (127.0.0.1:4420) [32808.317042] nvmet: creating controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:28ec29d001764c9dba1badd56054949b. [32808.331467] nvme nvme0: creating 12 I/O queues. [32808.339810] nvme nvme0: mapped 12/0/0 default/read/poll queues. [32808.351438] nvme nvme0: new ctrl: NQN "blktests-subsystem-1", addr 127.0.0.1:4420 [32810.288546] XFS (nvme0n1): Mounting V5 Filesystem [32810.302727] XFS (nvme0n1): Ending clean mount [32810.308744] xfs filesystem being mounted at /mnt/blktests supports timestamps until 2038 (0x7fffffff) [32870.677814] nvme nvme0: queue 1: timeout request 0x61 type 4 [32870.683500] nvme nvme0: starting error recovery [32870.688092] nvme nvme0: queue 4: timeout request 0x31 type 4 [32870.688657] block nvme0n1: no usable path - requeuing I/O [32870.694366] nvme nvme0: Reconnecting in 10 seconds... [32870.699182] block nvme0n1: no usable path - requeuing I/O [32870.699187] block nvme0n1: no usable path - requeuing I/O [32870.699193] block nvme0n1: no usable path - requeuing I/O [32870.720401] block nvme0n1: no usable path - requeuing I/O [32870.725810] block nvme0n1: no usable path - requeuing I/O [32870.731215] block nvme0n1: no usable path - requeuing I/O [32870.736627] block nvme0n1: no usable path - requeuing I/O [32870.742024] block nvme0n1: no usable path - requeuing I/O [32870.747431] block nvme0n1: no usable path - requeuing I/O [32896.277358] nvmet: ctrl 2 keep-alive timer (15 seconds) expired! [32896.283380] nvmet: ctrl 2 fatal error occurred! [32900.885454] nvmet: ctrl 1 keep-alive timer (15 seconds) expired! [32900.891465] nvmet: ctrl 1 fatal error occurred! [32924.104385] nvmet: creating controller 2 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:28ec29d001764c9dba1badd56054949b. [32942.358330] nvme nvme0: queue 0: timeout request 0x0 type 4 [32942.363969] nvme nvme0: Connect command failed, error wo/DNR bit: 881 [32942.370408] nvme nvme0: failed to connect queue: 0 ret=881 [32942.375910] nvme nvme0: Failed reconnect attempt 1 [32942.380688] nvme nvme0: Reconnecting in 10 seconds... [32952.599223] nvmet: creating controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:28ec29d001764c9dba1badd56054949b. [32952.613274] nvme_ns_head_submit_bio: 6 callbacks suppressed [32952.613282] block nvme0n1: no usable path - requeuing I/O [32952.624276] block nvme0n1: no usable path - requeuing I/O [32952.629679] block nvme0n1: no usable path - requeuing I/O [32952.635078] block nvme0n1: no usable path - requeuing I/O [32952.640484] block nvme0n1: no usable path - requeuing I/O [32952.645890] block nvme0n1: no usable path - requeuing I/O [32952.651300] block nvme0n1: no usable path - requeuing I/O [32952.656701] block nvme0n1: no usable path - requeuing I/O [32952.662107] block nvme0n1: no usable path - requeuing I/O [32952.667522] block nvme0n1: no usable path - requeuing I/O [32952.673156] nvme nvme0: creating 12 I/O queues. [32952.791830] nvme nvme0: mapped 12/0/0 default/read/poll queues. [32952.800343] nvme nvme0: Successfully reconnected (2 attempt) [33006.871736] nvme nvme0: queue 11: timeout request 0x22 type 4 [33006.877487] nvme nvme0: starting error recovery [33006.882487] nvme_ns_head_submit_bio: 14 callbacks suppressed [33006.882494] block nvme0n1: no usable path - requeuing I/O [33006.884161] nvme nvme0: Reconnecting in 10 seconds... [33006.888192] block nvme0n1: no usable path - requeuing I/O [33006.904052] block nvme0n1: no usable path - requeuing I/O [33006.909472] block nvme0n1: no usable path - requeuing I/O [33006.914902] block nvme0n1: no usable path - requeuing I/O [33006.920325] block nvme0n1: no usable path - requeuing I/O [33006.925739] block nvme0n1: no usable path - requeuing I/O [33006.931149] block nvme0n1: no usable path - requeuing I/O [33006.936567] block nvme0n1: no usable path - requeuing I/O [33006.941981] block nvme0n1: no usable path - requeuing I/O [33032.472272] nvmet: ctrl 2 keep-alive timer (15 seconds) expired! [33032.478284] nvmet: ctrl 2 fatal error occurred! [33035.032289] nvmet: ctrl 1 keep-alive timer (15 seconds) expired! [33035.038438] nvmet: ctrl 1 fatal error occurred! [33055.669945] nvmet: creating controller 2 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:28ec29d001764c9dba1badd56054949b. [33077.529217] nvme nvme0: queue 0: timeout request 0x1 type 4 [33077.534871] nvme nvme0: Connect command failed, error wo/DNR bit: 881 [33077.541363] nvme nvme0: failed to connect queue: 0 ret=881 [33077.546869] nvme nvme0: Failed reconnect attempt 1 [33077.551654] nvme nvme0: Reconnecting in 10 seconds... [33087.770043] nvmet: creating controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:28ec29d001764c9dba1badd56054949b. [33087.784153] nvme_ns_head_submit_bio: 1 callbacks suppressed [33087.784160] block nvme0n1: no usable path - requeuing I/O [33087.795145] block nvme0n1: no usable path - requeuing I/O [33087.800540] block nvme0n1: no usable path - requeuing I/O [33087.805938] block nvme0n1: no usable path - requeuing I/O [33087.811355] block nvme0n1: no usable path - requeuing I/O [33087.816745] block nvme0n1: no usable path - requeuing I/O [33087.822139] block nvme0n1: no usable path - requeuing I/O [33087.827521] block nvme0n1: no usable path - requeuing I/O [33087.832915] block nvme0n1: no usable path - requeuing I/O [33087.838310] block nvme0n1: no usable path - requeuing I/O [33087.843885] nvme nvme0: creating 12 I/O queues. [33087.912280] nvme nvme0: mapped 12/0/0 default/read/poll queues. [33087.914247] XFS (nvme0n1): Unmounting Filesystem [33087.923037] nvme nvme0: Successfully reconnected (2 attempt) [33088.069626] nvme nvme0: Removing ctrl: NQN "blktests-subsystem-1"