The kernel crashes due to the null-dereference occurred in GetSuperMagicFromDentry() from the 3rd party module namely b9k_87611

Issue

• The kernel crashes due to the null-dereference occurred in GetSuperMagicFromDentry() from the 3rd party module namely b9k_87611

[13614.017150] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
[13614.017258] PGD 0 P4D 0 
[13614.017320] Oops: 0000 [#1] SMP PTI
[13614.017390] CPU: 7 PID: 2308 Comm: pool-ds_am Kdump: loaded Tainted: P           OE    --------- -  - 4.18.0-305.10.2.el8_4.x86_64 #1
[13614.017497] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 12/12/2018
[13614.017655] RIP: 0010:GetSuperMagicFromDentry+0x3e/0x4f [b9k_87611]
[13614.017739] Code: f8 00 74 30 48 8b 45 f8 48 8b 40 30 48 85 c0 74 23 48 8b 45 f8 48 8b 40 30 48 8b 40 28 48 85 c0 74 12 48 8b 45 f8 48 8b 40 30 <48> 8b 40 28 48 8b 40 60 eb 05 b8 ff ff ff ff c9 c3 0f 1f 44 00 00
[13614.017924] RSP: 0018:ffffa5d24307fe00 EFLAGS: 00010286
[13614.018001] RAX: 0000000000000000 RBX: ffffffffc0973600 RCX: ffffffffc0ab7bd0
[13614.018089] RDX: ffffffffc0ab4652 RSI: ffffffffc0ab4720 RDI: ffff9773be889840
[13614.018178] RBP: ffffa5d24307fe08 R08: 0000000000000000 R09: 0000000000000000
[13614.019129] R10: ffff9773dd99aed8 R11: 0000000000000001 R12: 0000000000000000
[13614.019743] R13: ffff9773dd99aed8 R14: ffff97748f664020 R15: ffff9773be889840
[13614.020301] FS:  00007fad4f7fe700(0000) GS:ffff9774b5fc0000(0000) knlGS:0000000000000000
[13614.020859] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[13614.021394] CR2: 0000000000000028 CR3: 00000002017ac002 CR4: 00000000007706e0
[13614.021979] PKRU: 55555554
[13614.022524] Call Trace:
[13614.023113]  cbp_lsm_mmap_file+0x2ed/0x480 [b9k_87611]
[13614.023650]  cbstub_lsm_file_free_security+0x7f/0x8e [cbproxy_cbp_876_20211111]
[13614.024203]  security_file_free+0x22/0x30
[13614.024738]  __fput+0x12c/0x250
[13614.025271]  task_work_run+0x8a/0xb0
[13614.025794]  exit_to_usermode_loop+0xeb/0xf0
[13614.026314]  do_syscall_64+0x198/0x1a0
[13614.026829]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[13614.027370] RIP: 0033:0x7fad691a4bd7
[13614.027880] Code: 12 b8 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 3b c3 66 90 53 89 fb 48 83 ec 10 e8 c4 fb ff ff 89 df 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2b 89 d7 89 44 24 0c e8 06 fc ff ff 8b 44 24
[13614.028942] RSP: 002b:00007fad4f7fdc80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[13614.029486] RAX: 0000000000000000 RBX: 000000000000000f RCX: 00007fad691a4bd7
[13614.030076] RDX: 0000000000000000 RSI: 00007fad58013480 RDI: 000000000000000f
[13614.030733] RBP: 00007fad58006c20 R08: 00007fad5801bfd0 R09: 0000000000000007
[13614.031283] R10: 00000000006fd888 R11: 0000000000000293 R12: 00007fad6942ebb0
[13614.031835] R13: 00007ffc6948f77f R14: 0000000000000001 R15: 0000000000000001
[13614.032388] Modules linked in: veth xt_nat xt_conntrack ipt_MASQUERADE nf_conntrack_netlink nft_counter xt_addrtype nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables libcrc32c nfnetlink br_netfilter bridge stp llc overlay binfmt_misc b9k_87611(POE) cbproxy_cbp_876_20211111(POE) bmhook(OE) tmhook(OE) dsa_filter(POE) dsa_filter_hook(OE) sha512_ssse3 sha512_generic vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock sunrpc intel_rapl_msr intel_rapl_common isst_if_mbox_msr isst_if_common nfit libnvdimm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel rapl vmw_balloon joydev pcspkr vmw_vmci i2c_piix4 ip_tables ext4 mbcache jbd2 sr_mod cdrom ata_generic sd_mod vmwgfx t10_pi sg drm_kms_helper crc32c_intel syscopyarea sysfillrect sysimgblt fb_sys_fops ttm ahci serio_raw libahci drm ata_piix vmxnet3 libata vmw_pvscsi dm_mirror dm_region_hash dm_log dm_mod
[13614.036318] CR2: 0000000000000028