Kernel panic in _raw_spin_lock_irqsave() caused by third-party nslink kernel module

Issue

• Kernel crashed due to a NULL pointer dereference in the _raw_spin_lock_irqsave() function:

[81835.242327] BUG: unable to handle kernel NULL pointer dereference at 000000000000018c
[81835.242357] IP: [<ffffffff8edba982>] _raw_spin_lock_irqsave+0x22/0x40
[81835.242371] PGD 80000001c58e1067 PUD 2446ac067 PMD 0 
[81835.242382] Oops: 0002 [#1] SMP 
[81835.242389] Modules linked in: ip6table_filter ip6_tables iptable_filter tcp_diag udp_diag inet_diag bridge stp llc dsa_filter(POE) dsa_filter_hook(OE) nslink(OE) falcon_lsm_serviceable(PE) falcon_nf_netcontain(E) falcon_kal(E) falcon_lsm_pinned_17607(E) vfat fat ipmi_ssif iTCO_wdt iTCO_vendor_support intel_pmc_core intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm ses enclosure scsi_transport_sas irqbypass crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd pcspkr i2c_i801 cdc_ether usbnet mei_me mei sg mii idma64 i2c_designware_platform virt_dma i2c_designware_core pinctrl_cannonlake joydev wmi pinctrl_intel ipmi_si acpi_power_meter ipmi_devintf ipmi_msghandler video acpi_pad binfmt_misc ip_tables ext4 mbcache jbd2 sd_mod crc_t10dif crct10dif_generic
[81835.243141]  sr_mod cdrom mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm ahci libahci tg3 libata megaraid_sas uas crct10dif_pclmul crct10dif_common crc32c_intel ptp drm_panel_orientation_quirks pps_core i2c_hid usb_storage dm_mirror dm_region_hash dm_log dm_mod
[81835.244329] CPU: 9 PID: 9480 Comm: cat Kdump: loaded Tainted: P           OE  ------------   3.10.0-1160.134.1.el7.x86_64 #1
[81835.244911] Hardware name: Lenovo ThinkSystem ST250 -[7Y45CTO1WW]-/-[7Y45CTO1WW]-, BIOS -[ISE130E-2.81]- 05/31/2022
[81835.245492] task: ffff953544022100 ti: ffff953541158000 task.ti: ffff953541158000
[81835.246070] RIP: 0010:[<ffffffff8edba982>]  [<ffffffff8edba982>] _raw_spin_lock_irqsave+0x22/0x40
[81835.246652] RSP: 0018:ffff95354115bd50  EFLAGS: 00010046
[81835.246942] RAX: 0000000000000000 RBX: 0000000000000282 RCX: 0000000005b85be8
[81835.247231] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000018c
[81835.247511] RBP: ffff95354115bd58 R08: ffff95356645f1a0 R09: ffff95347fc03300
[81835.247790] R10: ffff95347fc03300 R11: ffffffff8e7ea045 R12: ffff9535445f2240
[81835.248066] R13: 0000000000000178 R14: ffff95354115be78 R15: ffff9535445f2240
[81835.248339] FS:  00007fd52d692740(0000) GS:ffff953566440000(0000) knlGS:0000000000000000
[81835.248912] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[81835.249188] CR2: 000000000000018c CR3: 00000001c5cca000 CR4: 00000000003607e0
[81835.249465] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[81835.249736] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[81835.249999] Call Trace:
[81835.250257]  [<ffffffffc0ae16fa>] hdlc_queue_proc_show+0x3a/0x190 [nslink]
[81835.250520]  [<ffffffff8e885798>] seq_read+0x138/0x460
[81835.250778]  [<ffffffff8e8d7870>] proc_reg_read+0x40/0x80
[81835.251029]  [<ffffffff8e85bc0f>] vfs_read+0x9f/0x170
[81835.251303]  [<ffffffff8e85ca85>] SyS_read+0x55/0xd0
[81835.251543]  [<ffffffffc0788c3e>] unload_network_ops_symbols+0x907e/0xbf80 [falcon_lsm_pinned_17607]
[81835.252039]  [<ffffffff8edc539f>] system_call_fastpath+0x25/0x2a
[81835.252274] Code: 5d c3 cc cc cc cc 0f 1f 00 0f 1f 44 00 00 55 48 89 e5 53 9c 58 0f 1f 44 00 00 48 89 c3 fa 66 0f 1f 44 00 00 31 c0 ba 01 00 00 00 <f0> 0f b1 17 85 c0 75 0a 48 89 d8 5b 5d c3 cc cc cc cc 89 c6 e8 
[81835.253015] RIP  [<ffffffff8edba982>] _raw_spin_lock_irqsave+0x22/0x40