Kernel panic in "bmhook_telemetry_scalar_add_value()" with BUG: unable to handle kernel NULL pointer dereference

Issue

• Kernel panicked with the below logs in RHEL 8:

crash> log -T | less
[..]
[Wed Jul 24 20:20:33 IST 2024] BUG: unable to handle kernel NULL pointer dereference at 000000000000006f
[Wed Jul 24 20:20:33 IST 2024] RIP: 0010:bmhook_telemetry_scalar_add_value+0xa/0x40 [bmhook]
[Wed Jul 24 20:20:33 IST 2024] Call Trace:
[Wed Jul 24 20:20:33 IST 2024]  ? __die_body+0x1a/0x60
[Wed Jul 24 20:20:33 IST 2024]  ? no_context+0x1ba/0x3f0
[Wed Jul 24 20:20:33 IST 2024]  ? bmhook_free_file_object+0x47/0x60 [bmhook]
[Wed Jul 24 20:20:33 IST 2024]  ? __bad_area_nosemaphore+0x157/0x180
[Wed Jul 24 20:20:33 IST 2024]  ? kmem_cache_free+0x116/0x300
[Wed Jul 24 20:20:33 IST 2024]  ? do_page_fault+0x37/0x12d
[Wed Jul 24 20:20:33 IST 2024]  ? page_fault+0x1e/0x30
[Wed Jul 24 20:20:33 IST 2024]  ? bmhook_telemetry_scalar_add_value+0xa/0x40 [bmhook]
[Wed Jul 24 20:20:33 IST 2024]  tmbpf_telemetry_scalar_add_value+0xa/0x20 [bmhook]
[Wed Jul 24 20:20:33 IST 2024]  ? bmhook_notifier_invoke_prog+0x1f8/0x230 [bmhook]
[Wed Jul 24 20:20:33 IST 2024]  ? process_exit_handler+0x69/0x160 [bmhook]
[Wed Jul 24 20:20:33 IST 2024]  ? notifier_call_chain+0x47/0x70
[Wed Jul 24 20:20:33 IST 2024]  ? blocking_notifier_call_chain+0x42/0x60
[Wed Jul 24 20:20:33 IST 2024]  ? do_exit+0xb0/0xb10
[Wed Jul 24 20:20:33 IST 2024]  ? syscall_trace_enter+0x1ff/0x2d0
[Wed Jul 24 20:20:33 IST 2024]  ? do_group_exit+0x3a/0xa0
[Wed Jul 24 20:20:33 IST 2024]  ? __x64_sys_exit_group+0x14/0x20
[Wed Jul 24 20:20:33 IST 2024]  ? do_syscall_64+0x5b/0x1b0
[Wed Jul 24 20:20:33 IST 2024]  ? entry_SYSCALL_64_after_hwframe+0x61/0xc6

• Kernel panicked with the below logs in RHEL 7:

crash> log | less

[..]
[  708.302611] BUG: unable to handle kernel paging request at ffffa1b286f26020
[  708.302664] RIP: 0010:[<ffffffffc07add3a>]  [<ffffffffc07add3a>] ScalarBaseEntryAddValue+0xa/0x30 [bmhook]
[  708.302700] Call Trace:
[  708.302707]  [<ffffffffc07ad208>] ? TelemetryScalarBaseEntryAddValue+0x18/0x20 [bmhook]
[  708.302713]  [<ffffffffc07861ed>] bmhook_telemetry_scalar_add_value+0x2d/0x40 [bmhook]
[  708.302718]  [<ffffffffc077d6fe>] tmbpf_telemetry_scalar_add_value+0xe/0x20 [bmhook]
[  708.302727]  [<ffffffffc078dced>] ? bmhook_prehook_handler+0x11d/0x430 [bmhook]
[  708.302734]  [<ffffffffc0282d93>] ? ext4_file_read+0x43/0x130 [ext4]
[  708.302737]  [<ffffffffc07337cc>] ? tmhook_invoke_prehooks+0x4c/0xb0 [tmhook]
[  708.302739]  [<ffffffffc0733db9>] ? tmhook_handler+0x189/0x2c0 [tmhook]
[  708.302743]  [<ffffffffb9b74ddb>] ? system_call_fastpath+0x22/0x27
[  708.302757] RIP  [<ffffffffc07add3a>] ScalarBaseEntryAddValue+0xa/0x30 [bmhook]
[  708.302762]  RSP <ffff885715a0fcc0>
[  708.302762] CR2: ffffa1b286f26020