The kernel crashes due to NULL pointer dereference happens in do_swap_page()

Issue

• We tried to force-reboot the RHEL guest from MS Azure console because the guest was hung up and inaccessible.
• The kernel crashed due to NULL pointer dereference happened in do_swap_page() just at that time.

[186737.455453] get_swap_device: Bad swap file entry 40022c71e1a67317
[186737.455459] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[186737.459639] PGD 43e774067 P4D 0 
[186737.461294] Oops: 0000 [#1] SMP NOPTI
[186737.463119] CPU: 4 PID: 16670 Comm: BW1_11_DIA_W20 Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-372.52.1.el8_6.x86_64 #1
[186737.469121] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 05/09/2022
[186737.474312] RIP: 0010:do_swap_page+0x432/0x710
[186737.476455] Code: 41 83 ce 08 e9 92 fe ff ff 48 8b 1c 24 48 89 df e8 53 dc fb ff 48 89 df e8 8b b8 ff ff e9 30 ff ff ff 4c 89 ef e8 ae e4 02 00 <48> 8b 00 f6 c4 08 74 11 4c 89 ef e8 ce a4 02 00 83 f8 01 0f 84 69
[186737.485544] RSP: 0000:ff7192934e37bd90 EFLAGS: 00010246
[186737.488039] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[186737.491492] RDX: 0000000000000000 RSI: ff4f3a8fffb16798 RDI: 0000000000000010
[186737.495102] RBP: ff7192934e37bdf0 R08: 0000000000000000 R09: c0000000ffff7fff
[186737.498599] R10: 0000000000000001 R11: ff7192934e37bb88 R12: ff4f3a884c1f7a48
[186737.502074] R13: 40022c71e1a67317 R14: 00007f88f9a00b68 R15: 0000000000000255
[186737.505673] FS:  00007f89d529e780(0000) GS:ff4f3a8fffb00000(0000) knlGS:0000000000000000
[186737.509347] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[186737.511795] CR2: 0000000000000000 CR3: 000000043e778003 CR4: 0000000000371ee0
[186737.514960] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[186737.517991] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[186737.521108] Call Trace:
[186737.522195]  ? pmd_devmap_trans_unstable+0x2e/0x40
[186737.524259]  ? handle_pte_fault+0x5d/0x880
[186737.526240]  __handle_mm_fault+0x453/0x6c0
[186737.528109]  handle_mm_fault+0xc1/0x1e0
[186737.529766]  do_user_addr_fault+0x1b9/0x450
[186737.531560]  do_page_fault+0x37/0x130
[186737.533142]  ? page_fault+0x8/0x30
[186737.534667]  page_fault+0x1e/0x30
[186737.536265] RIP: 0033:0x55d81b1c9c56
[186737.537812] Code: 8b 4e 08 4c 29 e9 48 3b 8b a8 00 00 00 0f 82 b9 00 00 00 f6 43 61 08 0f 85 af 00 00 00 4b 8d 34 2e b8 c0 ab ff ff 4d 89 6e 08 <48> 89 4e 08 4c 89 6e 10 66 89 06 48 89 4c 0e 10 4c 8b 8b d0 00 00
[186737.545593] RSP: 002b:00007fffa6813a80 EFLAGS: 00010246
[186737.547792] RAX: 00000000ffffabc0 RBX: 00007f88e7c38b98 RCX: 000000000022a350
[186737.550827] RDX: 000055d820d004a0 RSI: 00007f88f9a00b60 RDI: 0000000000000000
[186737.553892] RBP: 00007fffa6813d80 R08: 00007f88f99fdd60 R09: 0000000000000000
[186737.556971] R10: 00007f88ea027460 R11: 0000000000000000 R12: 000055d81bb3705d
[186737.560031] R13: 0000000000002e00 R14: 00007f88f99fdd60 R15: 00007f89ae430d78
[186737.563050] Modules linked in: [...]
[186737.596603] Red Hat flags: eBPF/rawtrace
[186737.598872] CR2: 0000000000000000
[186737.600957] ---[ end trace 31a6f8cd9bcddef4 ]---
[186737.603503] RIP: 0010:do_swap_page+0x432/0x710
[186737.606029] Code: 41 83 ce 08 e9 92 fe ff ff 48 8b 1c 24 48 89 df e8 53 dc fb ff 48 89 df e8 8b b8 ff ff e9 30 ff ff ff 4c 89 ef e8 ae e4 02 00 <48> 8b 00 f6 c4 08 74 11 4c 89 ef e8 ce a4 02 00 83 f8 01 0f 84 69
[186737.614902] RSP: 0000:ff7192934e37bd90 EFLAGS: 00010246
[186737.617889] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[186737.621435] RDX: 0000000000000000 RSI: ff4f3a8fffb16798 RDI: 0000000000000010
[186737.624978] RBP: ff7192934e37bdf0 R08: 0000000000000000 R09: c0000000ffff7fff
[186737.628701] R10: 0000000000000001 R11: ff7192934e37bb88 R12: ff4f3a884c1f7a48
[186737.632314] R13: 40022c71e1a67317 R14: 00007f88f9a00b68 R15: 0000000000000255
[186737.635835] FS:  00007f89d529e780(0000) GS:ff4f3a8fffb00000(0000) knlGS:0000000000000000
[186737.640279] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[186737.643262] CR2: 0000000000000000 CR3: 000000043e778003 CR4: 0000000000371ee0
[186737.646967] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[186737.650532] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[186737.654067] Kernel panic - not syncing: Fatal exception
[186737.657887] Kernel Offset: 0x27000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)