Kernel panic inside snapimage_done function due to null pointer dereference

Issue

• Kernel panic occurred with the following messages:

[3909945.756974] veeamsnap:blk        | WRN | Unable to freeze device [253:51]: no superblock was found
[3909945.952319] veeamsnap:snapimage  | ERR | Snapshot image for device was unexpectedly removed [0:0]
[3909945.952417] BUG: unable to handle kernel NULL pointer dereference at           (null)
[3909945.952425] IP: [<ffffffffc09ab460>] snapimage_done+0x60/0x160 [veeamsnap]
[3909945.952457] PGD 208d58067 PUD 323b97067 PMD 0 
[3909945.952464] Oops: 0002 [#1] SMP 
[3909945.952469] Modules linked in: secvm2(POE) secfs2(POE) seccrypto(POE) veeamsnap(OE-) xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter devlink ebtables dm_service_time ip6table_filter ip6_tables xt_comment iptable_filter vsock_diag tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi vmw_vsock_vmci_transport vsock sunrpc iosf_mbi crc32_pclmul ghash_clmulni_intel ppdev aesni_intel vmw_balloon lrw gf128mul glue_helper ablk_helper cryptd pcspkr joydev sg vmw_vmci i2c_piix4 parport_pc parport dm_multipath binfmt_misc ip_tables xfs libcrc32c sr_mod cdrom ata_generic pata_acpi
[3909945.952533]  vmwgfx drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops sd_mod ttm crc_t10dif crct10dif_generic ahci nfit libahci ata_piix drm crct10dif_pclmul crct10dif_common crc32c_intel libnvdimm libata serio_raw vmxnet3 vmw_pvscsi drm_panel_orientation_quirks floppy dm_mirror dm_region_hash dm_log dm_mod fuse [last unloaded: seccrypto]
[3909945.952570] CPU: 5 PID: 8554 Comm: rmmod Kdump: loaded Tainted: P           OE  ------------   3.10.0-1160.99.1.el7.x86_64 #1
[3909945.952575] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[3909945.952578] task: ffff927fa6dca100 ti: ffff9284e3890000 task.ti: ffff9284e3890000
[3909945.952582] RIP: 0010:[<ffffffffc09ab460>]  [<ffffffffc09ab460>] snapimage_done+0x60/0x160 [veeamsnap]
[3909945.952596] RSP: 0018:ffff9284e3893e98  EFLAGS: 00010246
[3909945.952599] RAX: 0000000000000000 RBX: ffff927e74802800 RCX: 0000000000000001
[3909945.952602] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffffc09c08a0
[3909945.952604] RBP: ffff9284e3893ea8 R08: ffff92823ce18500 R09: ffffffff82acc790
[3909945.952606] R10: 766f6d657220796c R11: 5d303a305b206465 R12: 0000000000000000
[3909945.952609] R13: 0000000000000800 R14: 0000000000000000 R15: 0000000000000000
[3909945.952613] FS:  00007fcd748ee740(0000) GS:ffff928719740000(0000) knlGS:0000000000000000
[3909945.952616] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[3909945.952618] CR2: 0000000000000000 CR3: 00000008fa4a8000 CR4: 00000000007607e0
[3909945.952676] PKRU: 55555554
[3909945.952679] Call Trace:
[3909945.952693]  [<ffffffffc09b5392>] cleanup_module+0x83/0xcf1 [veeamsnap]
[3909945.952723]  [<ffffffff82b2330e>] SyS_delete_module+0x19e/0x320
[3909945.952731]  [<ffffffff831c539a>] system_call_fastpath+0x25/0x2a
[3909945.952734] Code: 9b c0 44 89 c1 41 81 e0 ff ff 0f 00 c1 e9 14 e8 e7 1d ff ff 48 89 df e8 0f f5 ff ff 85 c0 41 89 c4 0f 85 c4 00 00 00 48 8b 43 28 <f0> ff 08 0f 94 c2 84 d2 74 0d 48 8b 78 08 48 8b 40 10 e8 09 2e 
[3909945.952781] RIP  [<ffffffffc09ab460>] snapimage_done+0x60/0x160 [veeamsnap]
[3909945.952793]  RSP <ffff9284e3893e98>
[3909945.952795] CR2: 0000000000000000