Kernel got panic while accessing encode_exchange_id()

Issue

• Kernel panic with logs:

[  558.233597] FS-Cache: N-cookie d=00000000546f0f63 n=0000000001f9259f
[  558.234242] FS-Cache: N-key=[16] '040000000200000002000801928ec84c'
[  667.993892] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[  667.995853] PGD 0 P4D 0 
[  667.997193] Oops: 0000 [#1] SMP PTI
[  667.998490] CPU: 1 PID: 15317 Comm: C2 CompilerThre Kdump: loaded Tainted: P           OE    --------- -  - 4.18.0-425.19.2.el8_7.x86_64 #1
[  668.000235] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[  668.001955] RIP: 0010:encode_exchange_id+0x104/0x1a0 [nfsv4]
[  668.003511] Code: 85 b8 00 00 00 48 81 c4 18 01 00 00 5b 5d 41 5c e9 61 1f c8 e0 65 48 8b 04 25 40 5c 01 00 48 8b 80 28 0b 00 00 be 0c 01 00 00 <48> 8b 40 08 48 8d 90 08 01 00 00 48 8d 48 04 52 4c 8d 88 c7 00 00
[  668.006174] RSP: 0018:ffffbda4052870d0 EFLAGS: 00010202
[  668.006865] RAX: 0000000000000000 RBX: ffffbda405287258 RCX: 0000000000000000
[  668.007599] RDX: ffffa050d573c090 RSI: 000000000000010c RDI: ffffbda405287258
[  668.008289] RBP: ffffa050b8cecb90 R08: 464e2078756e694c R09: 0000000000000006
[  668.009041] R10: ffffa050d573c086 R11: 7631307665647377 R12: ffffa050e2868680
[  668.009787] R13: ffffffffc07078b0 R14: ffffffffc06f9e10 R15: ffffffffc06f9e10
[  668.010523] FS:  0000000000000000(0000) GS:ffffa0536de40000(0000) knlGS:0000000000000000
[  668.011331] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  668.012057] CR2: 0000000000000008 CR3: 000000013e810006 CR4: 00000000007706e0
[  668.012772] PKRU: 55555554
[  668.013400] Call Trace:
[  668.014047]  ? rpc_release_client+0x3a/0x190 [sunrpc]
[  668.014960]  ? rpc_destroy_wait_queue+0x10/0x10 [sunrpc]
[  668.015695]  ? __rpc_execute+0x25f/0x460 [sunrpc]
[  668.016399]  ? mempool_alloc+0x67/0x180
[  668.017062]  ? __kmalloc+0x113/0x250
[  668.017765]  ? rpc_destroy_wait_queue+0x10/0x10 [sunrpc]
[  668.018491]  nfs4_xdr_enc_exchange_id+0x76/0xb0 [nfsv4]
[  668.019240]  rpcauth_wrap_req_encode+0x26/0x30 [sunrpc]
[  668.019979]  call_encode+0x16a/0x320 [sunrpc]
[  668.020624]  ? rpc_malloc+0x4d/0x90 [sunrpc]
[  668.021253]  __rpc_execute+0x78/0x460 [sunrpc]
[  668.021925]  rpc_execute+0xc7/0x100 [sunrpc]
[  668.022652]  rpc_run_task+0x13c/0x160 [sunrpc]
[  668.023377]  nfs4_run_exchange_id+0x1eb/0x2a0 [nfsv4]
[  668.024118]  _nfs4_proc_exchange_id+0x34/0x430 [nfsv4]
[  668.024889]  nfs41_discover_server_trunking+0x1c/0xa0 [nfsv4]
[  668.025685]  nfs4_discover_server_trunking+0x72/0x240 [nfsv4]
[  668.026419]  nfs4_init_client+0xbd/0x150 [nfsv4]
[  668.027105]  nfs4_set_ds_client+0x10d/0x160 [nfsv4]
[  668.027798]  ? call_function_single_interrupt+0xa/0x20
[  668.028433]  _nfs4_pnfs_v4_ds_connect+0x170/0x270 [nfsv4]
[  668.029073]  ? nfs4_find_get_deviceid+0x23d/0x460 [nfsv4]
[  668.029713]  ? kfree+0xd3/0x250
[  668.030277]  ? __nfs4_find_get_deviceid.isra.13+0x13/0x60 [nfsv4]
[  668.031017]  ? nfs4_find_get_deviceid+0x27e/0x460 [nfsv4]
[  668.031747]  ? bit_wait_io+0x50/0x50
[  668.032371]  nfs4_pnfs_ds_connect+0x195/0x350 [nfsv4]
[  668.032998]  ? pnfs_generic_pg_test+0x12/0x80 [nfsv4]
[  668.033629]  ? filelayout_pg_test+0x21/0xb0 [nfs_layout_nfsv41_files]
[  668.034257]  ? nfs_init_cinfo.part.32+0x42/0x60 [nfs]
[  668.034968]  nfs4_fl_prepare_ds+0x7c/0xa0 [nfs_layout_nfsv41_files]
[  668.035657]  filelayout_read_pagelist+0x53/0x140 [nfs_layout_nfsv41_files]
[  668.036337]  pnfs_generic_pg_readpages+0xa9/0x1e0 [nfsv4]
[  668.036956]  nfs_pageio_doio+0x3e/0x80 [nfs]
[  668.037549]  nfs_pageio_complete+0x78/0x130 [nfs]
[  668.038163]  nfs_pageio_complete_read+0xe/0x60 [nfs]
[  668.038751]  nfs_readpage+0x28b/0x350 [nfs]
[  668.039275]  generic_file_buffered_read+0x661/0xbb0
[  668.039827]  ? __nfs_revalidate_inode+0x156/0x290 [nfs]
[  668.040399]  nfs_file_read+0x72/0xa0 [nfs]
[  668.040912]  new_sync_read+0x10f/0x160
[  668.041411]  0xffffffffc0b10c95
[  668.041885]  ? 0xffffffffc0b10b01
[  668.042351]  ? cshook_systemcalltable_pre_compat_sys_ioctl+0x29aa8/0x320b0 [falcon_lsm_serviceable]
[  668.043015]  ? _ZdlPv+0x4055f/0x41980 [falcon_lsm_serviceable]
[  668.043591]  ? _ZdlPv+0x40751/0x41980 [falcon_lsm_serviceable]
[  668.044109]  ? cshook_systemcalltable_pre_compat_sys_ioctl+0x2922d/0x320b0 [falcon_lsm_serviceable]
[  668.044738]  ? __kmalloc+0x113/0x250
[  668.045278]  ? _ZdlPv+0x408da/0x41980 [falcon_lsm_serviceable]
[  668.045874]  ? _ZdlPv+0x40987/0x41980 [falcon_lsm_serviceable]
[  668.046424]  ? cshook_security_file_free_security+0x135/0x59e0 [falcon_lsm_serviceable]
[  668.047016]  ? pinnedhook_security_file_free_security+0x37/0x50 [falcon_lsm_pinned_15003]
[  668.047661]  ? security_file_free+0x22/0x60
[  668.048194]  ? __fput+0x12c/0x250
[  668.048715]  ? task_work_run+0x8a/0xb0
[  668.049238]  ? do_exit+0x34d/0xb10
[  668.049741]  ? do_group_exit+0x3a/0xa0
[  668.050238]  ? get_signal+0x158/0x870
[  668.050737]  ? do_futex+0x2f9/0x4d0
[  668.051240]  ? do_signal+0x36/0x690
[  668.051743]  ? audit_filter_inodes+0x2e/0x100
[  668.052255]  ? audit_reset_context.part.16+0x29f/0x2f0
[  668.052797]  ? exit_to_usermode_loop+0x89/0x100
[  668.053318]  ? do_syscall_64+0x19c/0x1b0
[  668.053850]  ? entry_SYSCALL_64_after_hwframe+0x61/0xc6
[  668.054420] Modules linked in: xt_connmark falcon_lsm_serviceable(PE) falcon_nf_netcontain(PE) falcon_kal(E) falcon_lsm_pinned_15003(E) ip_tables xt_LOG nf_log_syslog xt_multiport xt_mark xt_NFQUEUE xt_hashlimit nft_counter xt_conntrack nf_conntrack_ftp nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nfs_layout_nfsv41_files rpcsec_gss_krb5 auth_rpcgss nft_compat nfsv4 dns_resolver nfs lockd grace fscache mfe_aac_1007141206(OE) vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock nf_tables nfnetlink sunrpc intel_rapl_msr intel_rapl_common isst_if_mbox_msr isst_if_common nfit libnvdimm crc32_pclmul rapl vmw_balloon joydev pcspkr i2c_piix4 vmw_vmci binfmt_misc xfs libcrc32c crct10dif_pclmul crc32c_intel vmwgfx sr_mod cdrom ata_generic drm_ttm_helper ttm drm_kms_helper sd_mod t10_pi sg syscopyarea sysfillrect sysimgblt fb_sys_fops drm ghash_clmulni_intel ata_piix libata serio_raw vmxnet3 vmw_pvscsi dm_mirror dm_region_hash dm_log dm_mod fuse
[  668.060204] CR2: 0000000000000008