Kelsey, following the suggestion from bug 1956401, I've upgraded to 5.13.0-24-generic and it's exactly the same story as with 5.13.0-23:

    1.330735] BUG: kernel NULL pointer dereference, address: 000000000000000c
[    1.330768] #PF: supervisor write access in kernel mode
[    1.330788] #PF: error_code(0x0002) - not-present page
[    1.330809] PGD 0 P4D 0 
[    1.330822] Oops: 0002 [#1] SMP NOPTI
[    1.330838] CPU: 0 PID: 204 Comm: systemd-udevd Not tainted 5.13.0-24-generic #24-Ubuntu
[    1.330870] Hardware name: ASUSTeK COMPUTER INC. MINIPC PN50/PN50, BIOS 0623 05/13/2021
[    1.330900] RIP: 0010:amd_sfh_hid_client_init+0x47/0x350 [amd_sfh]
[    1.330930] Code: 00 53 48 83 ec 20 48 8b 5f 08 48 8b 07 48 8d b3 22 01 00 00 4c 8d b0 c8 00 00 00 e8 23 07 00 00 45 31 c0 31 c9 ba 00 00 20 00 <89> 43 0c 48 8d 83 68 01 00 00 48 8d bb 80 01 00 00 48 c7 c6 f0 6d
[    1.330997] RSP: 0018:ffffa523c0b939e0 EFLAGS: 00010246
[    1.331018] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[    1.331045] RDX: 0000000000200000 RSI: ffffffffc040c249 RDI: ffffffff9300004c
[    1.331072] RBP: ffffa523c0b93a28 R08: 0000000000000000 R09: 0000000000000006
[    1.331100] R10: ffffa523c0d00000 R11: 0000000000000007 R12: 0000000fffffffe0
[    1.331127] R13: ffff8a4ac11c5cd8 R14: ffff8a4ac11570c8 R15: ffff8a4ac11c5cd8
[    1.331154] FS:  00007feacb0ca8c0(0000) GS:ffff8a4dbf200000(0000) knlGS:0000000000000000
[    1.331184] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.331206] CR2: 000000000000000c CR3: 0000000117148000 CR4: 0000000000350ef0
[    1.331233] Call Trace:
[    1.331245]  <TASK>
[    1.331255]  ? __pci_set_master+0x5f/0xe0
[    1.331276]  amd_mp2_pci_probe+0xad/0x160 [amd_sfh]
[    1.331298]  local_pci_probe+0x48/0x80
[    1.331315]  pci_device_probe+0x105/0x1c0
[    1.331333]  really_probe+0x24b/0x4c0
[    1.331351]  driver_probe_device+0xf0/0x160
[    1.331369]  device_driver_attach+0xab/0xb0
[    1.331388]  __driver_attach+0xb2/0x140
[    1.331405]  ? device_driver_attach+0xb0/0xb0
[    1.331423]  bus_for_each_dev+0x7e/0xc0
[    1.331440]  driver_attach+0x1e/0x20
[    1.331458]  bus_add_driver+0x135/0x1f0
[    1.331475]  driver_register+0x95/0xf0
[    1.331492]  ? 0xffffffffc0411000
[    1.331506]  __pci_register_driver+0x57/0x60
[    1.331524]  amd_mp2_pci_driver_init+0x23/0x1000 [amd_sfh]
[    1.331548]  do_one_initcall+0x48/0x1d0
[    1.331566]  ? kmem_cache_alloc_trace+0xfb/0x240
[    1.331587]  do_init_module+0x62/0x290
[    1.331605]  load_module+0xa8f/0xb10
[    1.331621]  __do_sys_finit_module+0xc2/0x120
[    1.331641]  __x64_sys_finit_module+0x18/0x20
[    1.332883]  do_syscall_64+0x61/0xb0
[    1.334112]  ? fput+0x13/0x20
[    1.335316]  ? ksys_mmap_pgoff+0x135/0x260
[    1.336514]  ? exit_to_user_mode_prepare+0x37/0xb0
[    1.337702]  ? syscall_exit_to_user_mode+0x27/0x50
[    1.338877]  ? __x64_sys_mmap+0x33/0x40
[    1.340036]  ? do_syscall_64+0x6e/0xb0
[    1.341180]  ? do_syscall_64+0x6e/0xb0
[    1.342303]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[    1.343422] RIP: 0033:0x7feacb66094d
[    1.344527] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b3 64 0f 00 f7 d8 64 89 01 48
[    1.345707] RSP: 002b:00007ffc5c487aa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[    1.346879] RAX: ffffffffffffffda RBX: 000055ce67fb06d0 RCX: 00007feacb66094d
[    1.348048] RDX: 0000000000000000 RSI: 00007feacb7f03fe RDI: 0000000000000005
[    1.349211] RBP: 0000000000020000 R08: 0000000000000000 R09: 0000000000000000
[    1.349613] libphy: r8169: probed
[    1.350355] R10: 0000000000000005 R11: 0000000000000246 R12: 00007feacb7f03fe
[    1.351649] r8169 0000:02:00.0 eth0: RTL8168ep/8111ep, 24:4b:fe:c8:7e:6d, XID 502, IRQ 35
[    1.352626] R13: 000055ce67fc6440 R14: 000055ce67fe9420 R15: 000055ce67fe9760
[    1.352628]  </TASK>
[    1.352629] Modules linked in: amd_sfh(+) i2c_hid_acpi i2c_hid r8169(+) xhci_pci(+) realtek i2c_piix4 xhci_pci_renesas wmi(+) video(+)
[    1.353776] r8169 0000:02:00.0 eth0: jumbo features [frames: 9194 bytes, tx checksumming: ko]
[    1.354912]  fjes(+) hid
[    1.359502] CR2: 000000000000000c
[    1.360640] ---[ end trace 98bea865e3daeb73 ]---
[    1.361773] RIP: 0010:amd_sfh_hid_client_init+0x47/0x350 [amd_sfh]
[    1.362911] Code: 00 53 48 83 ec 20 48 8b 5f 08 48 8b 07 48 8d b3 22 01 00 00 4c 8d b0 c8 00 00 00 e8 23 07 00 00 45 31 c0 31 c9 ba 00 00 20 00 <89> 43 0c 48 8d 83 68 01 00 00 48 8d bb 80 01 00 00 48 c7 c6 f0 6d
[    1.364128] RSP: 0018:ffffa523c0b939e0 EFLAGS: 00010246
[    1.365338] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[    1.366562] RDX: 0000000000200000 RSI: ffffffffc040c249 RDI: ffffffff9300004c
[    1.367776] RBP: ffffa523c0b93a28 R08: 0000000000000000 R09: 0000000000000006
[    1.368986] R10: ffffa523c0d00000 R11: 0000000000000007 R12: 0000000fffffffe0
[    1.370180] R13: ffff8a4ac11c5cd8 R14: ffff8a4ac11570c8 R15: ffff8a4ac11c5cd8
[    1.371342] FS:  00007feacb0ca8c0(0000) GS:ffff8a4dbf200000(0000) knlGS:0000000000000000
[    1.372480] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.373613] CR2: 000000000000000c CR3: 0000000117148000 CR4: 0000000000350ef0