zram smoke test timed out on Artful thunderX arm64 (CPU soft lockup)

The ubuntu_zram_smoke_test will time out on Artful thunderX arm64 system.

11:34:44 DEBUG| [stdout] PASSED: zram module loaded
11:34:44 DEBUG| [stdout] PASSED: got 48 compression streams
11:34:44 DEBUG| [stdout] PASSED: got lzo lz4 deflate lz4hc 842 compression algorithmns
11:34:46 DEBUG| [stdout] PASSED: mkfs.ext4 on ZRAM successful
11:34:49 DEBUG| [stdout] PASSED: ext4 on ZRAM (lzo), memory used: 41945243 4230
11:34:51 DEBUG| [stdout] PASSED: mkfs.ext4 on ZRAM successful
11:34:53 DEBUG| [stdout] PASSED: ext4 on ZRAM (lz4), memory used: 41944958 3704
11:44:01 INFO | Timer expired (600 sec.), nuking pid 2544

CPU soft lockup trace could be found in syslog:
https://pastebin.ubuntu.com/p/fWhvvdjMQQ/

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-image-4.13.0-38-generic 4.13.0-38.43
ProcVersionSignature: User Name 4.13.0-38.43-generic 4.13.16
Uname: Linux 4.13.0-38-generic aarch64
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 Mar 22 10:21 seq
 crw-rw---- 1 root audio 116, 33 Mar 22 10:21 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay': 'aplay'
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: arm64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord': 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
Date: Thu Mar 22 11:36:53 2018
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig': 'iwconfig'
MachineType: Cavium ThunderX CRB
PciMultimedia:

ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
ProcFB:
 0 EFI VGA
 1 astdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-38-generic root=UUID=d4e5f461-24ef-47d8-a67f-42c82ff1efe8 ro
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-38-generic N/A
 linux-backports-modules-4.13.0-38-generic N/A
 linux-firmware 1.169.3
RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/12/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 5.11
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: To be filled by O.E.M.
dmi.board.vendor: To be filled by O.E.M.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To be filled by O.E.M.
dmi.chassis.type: 0
dmi.chassis.vendor: Cavium
dmi.chassis.version: To be filled by O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr5.11:bd12/12/2012:svnCavium:pnThunderXCRB:pvrTobefilledbyO.E.M.:rvnTobefilledbyO.E.M.:rnTobefilledbyO.E.M.:rvrTobefilledbyO.E.M.:cvnCavium:ct0:cvrTobefilledbyO.E.M.:
dmi.product.family: Default string
dmi.product.name: ThunderX CRB
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: Cavium