Hang in NVMe namespace deletion

Issue

• Hang in NVMe namespace deletion

crash> ps -m | grep UN
[0 00:00:00.000] [UN]  PID: 29745  TASK: ffff9a3197aba080  CPU: 32  COMMAND: "nvme"
[0 00:03:33.878] [UN]  PID: 30473  TASK: ffff9a19edf24100  CPU: 66  COMMAND: "reboot"

crash> bt ffff9a19edf24100
PID: 30473  TASK: ffff9a19edf24100  CPU: 66  COMMAND: "reboot"
 #0 [ffff9a19d5733b08] __schedule at ffffffffbcf676c7
 #1 [ffff9a19d5733b90] schedule at ffffffffbcf67bc9
 #2 [ffff9a19d5733ba0] rwsem_down_read_failed at ffffffffbcf691fd
 #3 [ffff9a19d5733c28] call_rwsem_down_read_failed at ffffffffbcb869a8
 #4 [ffff9a19d5733c78] down_read at ffffffffbcf66e80
 #5 [ffff9a19d5733c90] nvme_start_freeze at ffffffffc0164bf1 [nvme_core]
 #6 [ffff9a19d5733cb8] nvme_dev_disable at ffffffffc0255684 [nvme]
 #7 [ffff9a19d5733d70] nvme_shutdown at ffffffffc02557f2 [nvme]
 #8 [ffff9a19d5733d80] pci_device_shutdown at ffffffffbcbc4a5a
 #9 [ffff9a19d5733da8] device_shutdown at ffffffffbcca588b
#10 [ffff9a19d5733dd8] kernel_restart_prepare at ffffffffbc8b33e6
#11 [ffff9a19d5733de8] kernel_restart at ffffffffbc8b3402
#12 [ffff9a19d5733e00] SYSC_reboot at ffffffffbc8b3679
#13 [ffff9a19d5733f40] sys_reboot at ffffffffbc8b371e
#14 [ffff9a19d5733f50] system_call_fastpath at ffffffffbcf74ddb
    RIP: 00007f4e78949226  RSP: 00007ffc9feca868  RFLAGS: 00010206
    RAX: 00000000000000a9  RBX: 0000000000000004  RCX: 0000000000000000
    RDX: 0000000001234567  RSI: 0000000028121969  RDI: fffffffffee1dead
    RBP: 0000000000000004   R8: 00005639b85fd58c   R9: 0000000000000000
    R10: 0000000000000024  R11: 0000000000000206  R12: 0000000000000000
    R13: 00007ffc9fecb590  R14: 0000000000000000  R15: 0000000000000000
    ORIG_RAX: 00000000000000a9  CS: 0033  SS: 002b

crash> bt ffff9a3197aba080
PID: 29745  TASK: ffff9a3197aba080  CPU: 32  COMMAND: "nvme"
 #0 [ffff9a319c3b38d8] __schedule at ffffffffbcf676c7
 #1 [ffff9a319c3b3968] schedule at ffffffffbcf67bc9
 #2 [ffff9a319c3b3978] schedule_timeout at ffffffffbcf655e8
 #3 [ffff9a319c3b3a28] io_schedule_timeout at ffffffffbcf6726d
 #4 [ffff9a319c3b3a58] wait_for_completion_io_timeout at ffffffffbcf680c5
 #5 [ffff9a319c3b3ab8] blk_execute_rq at ffffffffbcb4b1bb
 #6 [ffff9a319c3b3b70] __nvme_submit_sync_cmd at ffffffffc01638cf [nvme_core]
 #7 [ffff9a319c3b3bb0] nvme_identify_ns at ffffffffc0165eed [nvme_core]
 #8 [ffff9a319c3b3c40] nvme_revalidate_disk at ffffffffc0165f81 [nvme_core]
 #9 [ffff9a319c3b3cf0] nvme_user_cmd at ffffffffc0167c36 [nvme_core]
#10 [ffff9a319c3b3e00] nvme_ioctl at ffffffffc0168046 [nvme_core]
#11 [ffff9a319c3b3e10] blkdev_ioctl at ffffffffbcb5726a
#12 [ffff9a319c3b3e70] block_ioctl at ffffffffbca80761
#13 [ffff9a319c3b3e80] do_vfs_ioctl at ffffffffbca56210
#14 [ffff9a319c3b3f00] sys_ioctl at ffffffffbca564b1
#15 [ffff9a319c3b3f50] system_call_fastpath at ffffffffbcf74ddb
    RIP: 00007fa4584f18d7  RSP: 00007ffeac8cd3d8  RFLAGS: 00010202
    RAX: 0000000000000010  RBX: 0000000000000003  RCX: 00007fa4584f18d7
    RDX: 00007ffeac8cd380  RSI: 00000000c0484e41  RDI: 0000000000000003
    RBP: 00000000ffffffea   R8: 000000000000000f   R9: 0000000000000003
    R10: 00007ffeac8cc7a0  R11: 0000000000000246  R12: 000000000065cc40
    R13: 000000000000000c  R14: 0000000000000002  R15: 000000000065cc40
    ORIG_RAX: 0000000000000010  CS: 0033  SS: 002b