RHEL7: kernel panic at fsnotify+0xa0 when using mvfs 3rd party module.

Issue

• kernel panic occurred with following logs:

[2245917.070741] BUG: unable to handle kernel NULL pointer dereference at 0000000000000230
[2245917.070744] IP: [<ffffffffa0695de0>] fsnotify+0xa0/0x460
[2245917.070749] PGD 1ba830067 PUD be50e9067 PMD 0 
[2245917.070751] Oops: 0000 [#1] SMP 
[2245917.070753] Modules linked in: binfmt_misc nvidia_uvm(POE) fuse rpcsec_gss_krb5 nfsv4 dns_resolver mvfs(OE) nfsv3 nfs fscache iTCO_wdt iTCO_vendor_support nvidia_drm(POE) nvidia_modeset(POE) snd_hda_codec_hdmi nfit libnvdimm nvidia(POE) intel_powerclamp coretemp intel_rapl iosf_mbi drm_kms_helper kvm syscopyarea sysfillrect sysimgblt fb_sys_fops drm snd_hda_codec_realtek irqbypass crc32_pclmul snd_hda_codec_generic ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd drm_panel_orientation_quirks snd_hda_intel ipmi_devintf hp_wmi sparse_keymap snd_hda_codec rfkill ipmi_msghandler snd_seq intel_wmi_thunderbolt pcspkr snd_hda_core snd_seq_device snd_hwdep snd_pcm joydev sg snd_timer mei_me snd mei i2c_i801 soundcore tpm_crb nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables
[2245917.070779]  ext4 mbcache jbd2 dm_snapshot dm_bufio sd_mod crc_t10dif crct10dif_generic e1000e igb nvme crct10dif_pclmul ahci crct10dif_common crc32c_intel libahci nvme_core dca serio_raw libata ptp pps_core i2c_algo_bit wmi dm_mirror dm_region_hash dm_log dm_mod
[2245917.070791] CPU: 18 PID: 20386 Comm: rg Kdump: loaded Tainted: P           OE  ------------   3.10.0-1127.el7.x86_64 #1
[2245917.070792] Hardware name: HP HP Z4 G4 Workstation/81C5, BIOS P62 v02.46 01/27/2020
[2245917.070793] task: ffff8ae6b7035230 ti: ffff8ad916fe8000 task.ti: ffff8ad916fe8000
[2245917.070794] RIP: 0010:[<ffffffffa0695de0>]  [<ffffffffa0695de0>] fsnotify+0xa0/0x460
[2245917.070796] RSP: 0018:ffff8ad916febdd8  EFLAGS: 00010246
[2245917.070797] RAX: 0000000000000000 RBX: ffff8ae674443180 RCX: 0000000000000001
[2245917.070798] RDX: ffff8ada0bbaa110 RSI: 0000000000020000 RDI: 0000000000000000
[2245917.070799] RBP: ffff8ad916febe80 R08: 0000000000000000 R09: 0000000000000000
[2245917.070800] R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000020000
[2245917.070801] R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
[2245917.070802] FS:  00007ffff27ffb20(0000) GS:ffff8ae6bea80000(0000) knlGS:0000000000000000
[2245917.070803] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[2245917.070804] CR2: 0000000000000230 CR3: 0000000ecee38000 CR4: 00000000003607e0
[2245917.070805] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[2245917.070806] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[2245917.070807] Call Trace:
[2245917.070812]  [<ffffffffa0707c7c>] security_file_permission+0x8c/0xa0
[2245917.070815]  [<ffffffffa0662b23>] iterate_dir+0x43/0x130
[2245917.070817]  [<ffffffffa06631bc>] SyS_getdents64+0x9c/0x120
[2245917.070818]  [<ffffffffa0662e30>] ? fillonedir+0x110/0x110
[2245917.070822]  [<ffffffffa0b92ed2>] system_call_fastpath+0x25/0x2a
[2245917.070823] Code: 00 f7 44 24 4c 00 00 00 08 48 8b 44 24 40 74 1b 48 83 b8 30 02 00 00 00 0f 84 59 03 00 00 31 db eb 17 66 0f 1f 84 00 00 00 00 00 <48> 83 b8 30 02 00 00 00 0f 84 2b 03 00 00 44 8b 6c 24 4c 41 83 
[2245917.070839] RIP  [<ffffffffa0695de0>] fsnotify+0xa0/0x460
[2245917.070840]  RSP <ffff8ad916febdd8>
[2245917.070841] CR2: 0000000000000230