Kernel panics in page_array_memset() function while taking backup.

Issue

• System panics with following messages :

[  531.624984] Request for unknown module key 'Veeam Software AG: 9d063645550b483bec752cb3c0249d5ede714b3e' err -11
[  531.624997] veeamsnap: loading out-of-tree module taints kernel.
[  531.625001] WARNING: module 'veeamsnap' built without retpoline-enabled compiler, may affect Spectre v2 mitigation   <<------
[  531.625734] veeamsnap: module verification failed: signature and/or required key missing - tainting kernel  <<-------
[  531.625963] veeamsnap: applying kernel_stack fix up
[  531.627674]     veeamsnap:veeamsnap_init Loading
[  531.627677]     veeamsnap:veeamsnap_init Version: 2.0.0.400
[  531.627679]     veeamsnap:veeamsnap_init Author: Veeam Software AG
[  531.627681]     veeamsnap:veeamsnap_init licence: GPL
[  531.627683]     veeamsnap:veeamsnap_init description: Veeam Snapshot Kernel Module
[  531.627685]     veeamsnap:veeamsnap_init zerosnapdata: 1
[  531.627687]     veeamsnap:veeamsnap_init debuglogging: 0
[  531.627688]     veeamsnap:veeamsnap_init snapstore enabled
[  531.627690]     veeamsnap:veeamsnap_init start. container_alloc_counter=0
[  531.627692]     veeamsnap:veeamsnap_init start. container_sl_alloc_counter=0
[  531.627694]     veeamsnap:veeamsnap_init start. mem_cnt=0
[  531.627695]     veeamsnap:veeamsnap_init start. vmem_cnt=0
[  531.627697]     veeamsnap:ctrl_pipe_init .
[  531.627701]     veeamsnap:veeamsnap_init Module major=241
[  531.628335]     veeamsnap:blk_direct_bioset_create Specific bio set created.
[  531.628391]     veeamsnap:blk_redirect_bioset_create Specific bio set created.
[  531.628449]     veeamsnap:blk_deferred_bioset_create Specific bio set created.
[  531.628457]     veeamsnap:snapimage_init .
[  531.628460]     veeamsnap:snapimage_init Snapimage block device was registered. major=252
[  531.628464]     veeamsnap:veeamsnap_init end. container_alloc_counter=0
[  531.628466]     veeamsnap:veeamsnap_init end. container_sl_alloc_counter=0
[  531.628467]     veeamsnap:veeamsnap_init end. mem_cnt=1
[  531.628469]     veeamsnap:veeamsnap_init end. vmem_cnt=0
[  531.635536]     veeamsnap:ctrl_open file=0xffff8d5d4d0cd700
[  531.635542]     veeamsnap:ctrl_pipe_new .
[  531.635586]     veeamsnap:ioctl_compatibility_flags Get compatibility flags   <<-------
[  531.635739]     veeamsnap:ioctl_tracking_collect Collecting tracking device:
[  531.635746]     veeamsnap:tracking_collect Have not device under CBT.
[  531.639239]     veeamsnap:tracking_add Adding. dev_id=8:1
[  531.639251]     veeamsnap:tracker_Create dev_id 8:1
[  531.639253]     veeamsnap:tracker_Create SectorStart    =0x800
[  531.639255]     veeamsnap:tracker_Create SectorsCapacity=0xfa000
[  531.639257]     veeamsnap:tracker_cbt_start .
[  531.639259]     veeamsnap:cbt_map_create CBT map create.
[  531.639277] general protection fault: 0000 [#1] SMP 
[  531.639439] Modules linked in: veeamsnap(OE) mptctl mptbase intel_powerclamp coretemp kvm_intel kvm iTCO_wdt 
 ............
[  531.641458] CPU: 3 PID: 13085 Comm: Lpb Server thre Kdump: loaded Tainted: G          IOE  ------------   3.10.0-862.3.2.el7.x86_64 #1
[  531.641799] Hardware name: HP ProLiant DL360 G7, BIOS P68 08/16/2015
[  531.641981] task: ffff8d5c80040000 ti: ffff8d5d39c00000 task.ti: ffff8d5d39c00000
[  531.642193] RIP: 0010:[<ffffffffc069eebd>]  [<ffffffffc069eebd>] page_array_memset+0x4d/0xa0 [veeamsnap]
[  531.642479] RSP: 0018:ffff8d5d39c03d60  EFLAGS: 00010246
 ............
[  531.644240] Call Trace:
[  531.644319]  [<ffffffffc06a49ce>] cbt_map_allocate+0x6e/0x160 [veeamsnap]
[  531.644516]  [<ffffffffc06a4c03>] cbt_map_create+0x73/0x100 [veeamsnap]
[  531.644710]  [<ffffffffc06a55ba>] tracker_cbt_start+0x5a/0xc0 [veeamsnap]
[  531.644907]  [<ffffffffc06a5b6a>] tracker_Create+0x16a/0x650 [veeamsnap]
[  531.645101]  [<ffffffffc06b29b0>] tracking_add+0x2e0/0x450 [veeamsnap]
[  531.645292]  [<ffffffffc06b36fc>] ioctl_tracking_add+0x6c/0x170 [veeamsnap]
[  531.645494]  [<ffffffffc06b611e>] ctrl_unlocked_ioctl+0x4e/0x60 [veeamsnap]
[  531.645696]  [<ffffffffb462fed0>] do_vfs_ioctl+0x350/0x560
[  531.645855]  [<ffffffffb46d86ff>] ? file_has_perm+0x9f/0xb0
[  531.646017]  [<ffffffffb461df11>] ? __sb_end_write+0x31/0x60
[  531.646180]  [<ffffffffb4630181>] SyS_ioctl+0xa1/0xc0
[  531.646328]  [<ffffffffb4b2076f>] ? system_call_after_swapgs+0xbc/0x160
[  531.646517]  [<ffffffffb4b2082f>] system_call_fastpath+0x1c/0x21
[  531.646690]  [<ffffffffb4b2077b>] ? system_call_after_swapgs+0xc8/0x160
[  531.646877] Code: 01 49 89 f9 48 0f af c2 49 8b 79 10 ba 00 10 00 00 40 f6 c7 01 75 47 40 f6 c7 02 75 51 40 f6 c7 04 75 2b 89 d1 c1 e9 03 83 e2 07 <f3> 48 ab 74 0e 41 89 c8 83 c1 01 39 d1 42 88 34 07 72 f2 49 83 
[  531.647982] RIP  [<ffffffffc069eebd>] page_array_memset+0x4d/0xa0 [veeamsnap]
[  531.648197]  RSP <ffff8d5d39c03d60>