Unmounting the filesystem while the tracepoint is active gives us "VFS: Busy inodes after unmount..." message followed by the null-ptr defer and the crash

Issue

• Unmounting the filesystem while the tracepoint is active gives us "VFS: Busy inodes after unmount..." message followed by the null-ptr defer and the crash

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[ 7770.557665] XFS (dm-17): Unmounting Filesystem
[ 7770.796021] XFS (dm-21): Unmounting Filesystem
[ 7771.507835] XFS (dm-20): Unmounting Filesystem
[ 7771.785872] VFS: Busy inodes after unmount of dm-20. Self-destruct in 5 seconds.  Have a nice day...
[ 7772.076417] XFS (dm-22): Unmounting Filesystem
[ 7772.133742] XFS (dm-26): Unmounting Filesystem
[ 7772.162195] XFS (dm-19): Unmounting Filesystem
[ 7772.187072] XFS (dm-18): Unmounting Filesystem
[ 7772.214784] XFS (dm-2): Unmounting Filesystem
[ 7772.235725] XFS (dm-13): Unmounting Filesystem
[ 7772.252872] XFS (dm-4): Unmounting Filesystem
[ 7772.274931] XFS (dm-5): Unmounting Filesystem
[ 7772.293772] XFS (dm-6): Unmounting Filesystem
[ 7772.307776] XFS (dm-7): Unmounting Filesystem
[ 7772.325715] XFS (dm-12): Unmounting Filesystem
[ 7772.342847] XFS (dm-25): Unmounting Filesystem
[ 7772.360904] XFS (dm-11): Unmounting Filesystem
[ 7772.377732] XFS (dm-8): Unmounting Filesystem
[ 7772.391797] XFS (dm-9): Unmounting Filesystem
[ 7772.410798] XFS (dm-10): Unmounting Filesystem
[ 7772.473575] XFS (dm-3): Unmounting Filesystem
[ 7772.492586] XFS (dm-15): Unmounting Filesystem
[ 7772.522586] XFS (dm-14): Unmounting Filesystem
[ 7772.536696] XFS (dm-16): Unmounting Filesystem
[ 7772.558882] XFS (dm-24): Unmounting Filesystem
[ 7772.686824] BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
[ 7772.688927] IP: [<ffffffff82f8ed0c>] _raw_spin_lock+0xc/0x30
[ 7772.691071] PGD 0 
[ 7772.693168] Oops: 0002 [#1] SMP 
[ 7772.694811] Modules linked in: bmhook(OE) tmhook(OE) gc_enforcement(OE) dsa_filter(POE) dsa_filter_hook(OE) nf_conntrack_ipv6 nf_defrag_ipv6 vsock_diag tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables devlink ip6table_filter ip6_tables iptable_filter vmw_vsock_vmci_transport vsock sunrpc nfit libnvdimm iosf_mbi crc32_pclmul ppdev ghash_clmulni_intel aesni_intel lrw vmw_balloon gf128mul pcspkr glue_helper joydev ablk_helper cryptd sg vmw_vmci parport_pc parport i2c_piix4 binfmt_misc ip_tables xfs libcrc32c sr_mod cdrom ata_generic pata_acpi vmwgfx drm_kms_helper
[ 7772.700446]  syscopyarea sysfillrect sysimgblt fb_sys_fops sd_mod ttm crc_t10dif crct10dif_generic drm ata_piix libata crct10dif_pclmul crct10dif_common crc32c_intel serio_raw vmxnet3 vmw_pvscsi drm_panel_orientation_quirks floppy dm_mirror dm_region_hash dm_log dm_mod fuse
[ 7772.702839] CPU: 8 PID: 7638 Comm: ds_nuagent Kdump: loaded Tainted: P           OE  ------------ T 3.10.0-1160.71.1.el7.x86_64 #1
[ 7772.704036] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/21/2015
[ 7772.704998] task: ffff937b7ce83180 ti: ffff937b2ccdc000 task.ti: ffff937b2ccdc000
[ 7772.705822] RIP: 0010:[<ffffffff82f8ed0c>]  [<ffffffff82f8ed0c>] _raw_spin_lock+0xc/0x30
[ 7772.706658] RSP: 0018:ffff937b2ccdfb58  EFLAGS: 00010246
[ 7772.707506] RAX: 0000000000000000 RBX: ffff937a5f920800 RCX: 0000000000000034
[ 7772.708327] RDX: 0000000000000001 RSI: ffff937a609ef9e8 RDI: 0000000000000058
[ 7772.709151] RBP: ffff937b2ccdfb78 R08: d018000000000000 R09: 7a609ef9e80c0000
[ 7772.709969] R10: 0000000000000000 R11: fff00000f0000000 R12: ffff937a5f9207f8
[ 7772.710884] R13: 0000000000000058 R14: ffffffffc04433e0 R15: 0000000000000001
[ 7772.711717] FS:  00007fbcf9395f38(0000) GS:ffff937c2fc00000(0000) knlGS:0000000000000000
[ 7772.712532] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7772.713342] CR2: 0000000000000058 CR3: 000000031f180000 CR4: 00000000003607e0
[ 7772.714194] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 7772.715007] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 7772.715795] Call Trace:
[ 7772.716590]  [<ffffffff82b0ed3e>] ? selinux_inode_free_security+0x2e/0x70
[ 7772.717437]  [<ffffffff82b08b18>] security_inode_free+0x28/0x30
[ 7772.718237]  [<ffffffff82a6c532>] __destroy_inode+0x22/0xf0
[ 7772.719025]  [<ffffffff82a6c622>] destroy_inode+0x22/0x60
[ 7772.719798]  [<ffffffff82a6c775>] evict+0x115/0x180
[ 7772.720566]  [<ffffffff82a6cb4c>] iput+0xfc/0x190
[ 7772.721330]  [<ffffffff8298d5eb>] free_trace_uprobe+0x4b/0x80
[ 7772.722127]  [<ffffffff8298dfd6>] unregister_trace_uprobe+0x46/0x50
[ 7772.722966]  [<ffffffff8298edb2>] create_trace_uprobe+0x712/0x7c0
[ 7772.723734]  [<ffffffff8295a19f>] ? synchronize_sched_expedited+0x17f/0x1e0
[ 7772.724492]  [<ffffffff82a2af45>] ? __kmalloc_track_caller+0x55/0x240
[ 7772.725288]  [<ffffffff82b86081>] ? argv_split+0x21/0x130
[ 7772.726102]  [<ffffffff82a28b75>] ? __kmalloc+0x55/0x230
[ 7772.726926]  [<ffffffff82b860f4>] ? argv_split+0x94/0x130
[ 7772.727767]  [<ffffffff8298e6a0>] ? alloc_trace_uprobe+0x1c0/0x1c0
[ 7772.728586]  [<ffffffff8298d138>] traceprobe_command+0x78/0x90
[ 7772.729402]  [<ffffffff8298d1cc>] traceprobe_probes_write+0x7c/0x160
[ 7772.730200]  [<ffffffff8298e6a0>] ? alloc_trace_uprobe+0x1c0/0x1c0
[ 7772.730989]  [<ffffffff8298d790>] probes_write+0x10/0x20
[ 7772.731776]  [<ffffffff82a4e4d0>] vfs_write+0xc0/0x1f0
[ 7772.732529]  [<ffffffff82a4f255>] SyS_write+0x55/0xd0
[ 7772.733213]  [<ffffffff82f8b8b2>] ? down_read+0x12/0x40
[ 7772.733912]  [<ffffffffc08c8cf5>] tmhook_invoke.isra.8+0x45/0x90 [tmhook]
[ 7772.734644]  [<ffffffffc08c8ee8>] tmhook_handler+0x1a8/0x2c0 [tmhook]
[ 7772.735365]  [<ffffffff82a506e5>] ? __fput+0x195/0x230
[ 7772.736014]  [<ffffffff82f99f92>] system_call_fastpath+0x25/0x2a
[ 7772.736634] Code: 5d c3 0f 1f 44 00 00 85 d2 74 e4 0f 1f 40 00 eb ed 66 0f 1f 44 00 00 b8 01 00 00 00 5d c3 90 0f 1f 44 00 00 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 58 20 ff ff 5d 
[ 7772.738137] RIP  [<ffffffff82f8ed0c>] _raw_spin_lock+0xc/0x30
[ 7772.738764]  RSP <ffff937b2ccdfb58>
[ 7772.739406] CR2: 0000000000000058
    ...