root@talos:~ # sysctl dev.nvme.0.ioq0.cq_head dev.nvme.0.ioq0.sq_head dev.nvme.0.ioq0.sq_tail
nvme0: cpl does not map to outstanding cmd
cdw0:00000000 sqhd:008d sqid:0001 cid:001c p:0 sc:00 sct:0 m:0 dnr:0
panic: received completion for unknown cmd

cpuid = 19
time = 1529184196
KDB: stack backtrace:
0xe0000000002a6290: at .kdb_backtrace+0x5c
0xe0000000002a63c0: at .vpanic+0x1b4
0xe0000000002a6480: at .kassert_panic+0xf8
0xe0000000002a6520: at .nvme_qpair_process_completions+0x148
0xe0000000002a65c0: at .nvme_ctrlr_poll+0x64
0xe0000000002a6650: at .nvme_ctrlr_intx_handler+0x50
0xe0000000002a66e0: at .intr_event_execute_handlers+0x184
0xe0000000002a6780: at .intr_event_add_handler+0x52c
0xe0000000002a6850: at .fork_exit+0xd0
0xe0000000002a68f0: at .fork_trampoline+0x10
0xe0000000002a6920: at -0x4
KDB: enter: panic
[ thread pid 12 tid 100179 ]
Stopped at      .breakpoint+0x50:       ld      r1, r0, 0x1f8
db>