reuseport_bpf_cpu in net from ubuntu_kernel_selftests failed on 4.15 / 5.3 / 5.4 PowerPC

Issue found on 4.15.0-97-generic X-hwe-4.15 with P8 node modoc:

$ sudo ./reuseport_bpf_cpu
---- IPv4 UDP ----
send cpu 0, receive socket 0
send cpu 1, receive socket 1
send cpu 2, receive socket 2
send cpu 3, receive socket 3
send cpu 4, receive socket 4
send cpu 5, receive socket 5
send cpu 6, receive socket 6
send cpu 7, receive socket 7
send cpu 8, receive socket 8
send cpu 9, receive socket 9
send cpu 10, receive socket 10
send cpu 11, receive socket 11
send cpu 12, receive socket 12
send cpu 13, receive socket 13
send cpu 14, receive socket 14
send cpu 15, receive socket 15
send cpu 16, receive socket 16
send cpu 17, receive socket 17
send cpu 18, receive socket 18
send cpu 19, receive socket 19
send cpu 20, receive socket 20
send cpu 21, receive socket 21
send cpu 22, receive socket 22
send cpu 23, receive socket 23
send cpu 24, receive socket 24
send cpu 25, receive socket 25
send cpu 26, receive socket 26
send cpu 27, receive socket 27
send cpu 28, receive socket 28
send cpu 29, receive socket 29
send cpu 30, receive socket 30
send cpu 31, receive socket 31
send cpu 32, receive socket 32
send cpu 33, receive socket 33
send cpu 34, receive socket 34
send cpu 35, receive socket 35
send cpu 36, receive socket 36
send cpu 37, receive socket 37
send cpu 38, receive socket 38
send cpu 39, receive socket 39
send cpu 40, receive socket 40
send cpu 41, receive socket 41
send cpu 42, receive socket 42
send cpu 43, receive socket 43
send cpu 44, receive socket 44
send cpu 45, receive socket 45
send cpu 46, receive socket 46
send cpu 47, receive socket 47
send cpu 48, receive socket 48
send cpu 49, receive socket 49
send cpu 50, receive socket 50
send cpu 51, receive socket 51
send cpu 52, receive socket 52
send cpu 53, receive socket 53
send cpu 54, receive socket 54
send cpu 55, receive socket 55
send cpu 56, receive socket 56
send cpu 57, receive socket 57
send cpu 58, receive socket 58
send cpu 59, receive socket 59
send cpu 60, receive socket 60
send cpu 61, receive socket 61
send cpu 62, receive socket 62
send cpu 63, receive socket 63
send cpu 64, receive socket 64
send cpu 65, receive socket 65
send cpu 66, receive socket 66
send cpu 67, receive socket 67
send cpu 68, receive socket 68
send cpu 69, receive socket 69
send cpu 70, receive socket 70
send cpu 71, receive socket 71
send cpu 72, receive socket 72
send cpu 73, receive socket 73
send cpu 74, receive socket 74
send cpu 75, receive socket 75
send cpu 76, receive socket 76
send cpu 77, receive socket 77
send cpu 78, receive socket 78
send cpu 79, receive socket 79
send cpu 80, receive socket 80
send cpu 81, receive socket 81
send cpu 82, receive socket 82
send cpu 83, receive socket 83
send cpu 84, receive socket 84
send cpu 85, receive socket 85
send cpu 86, receive socket 86
send cpu 87, receive socket 87
./reuseport_bpf_cpu: failed to pin to cpu: Invalid argument

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.15.0-97-generic 4.15.0-97.98~16.04.1
ProcVersionSignature: Ubuntu 4.15.0-97.98~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-97-generic ppc64le
ApportVersion: 2.20.1-0ubuntu2.23
Architecture: ppc64el
Date: Tue Apr 14 07:30:49 2020
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcLoadAvg: 0.25 0.22 0.10 1/1267 4640
ProcLocks:
 1: POSIX ADVISORY WRITE 3251 00:17:581 0 EOF
 2: POSIX ADVISORY WRITE 2065 00:17:389 0 EOF
 3: POSIX ADVISORY WRITE 3254 00:17:595 0 EOF
 4: POSIX ADVISORY WRITE 3359 00:17:598 0 EOF
 5: FLOCK ADVISORY WRITE 3243 00:17:586 0 EOF
ProcSwaps:
 Filename Type Size Used Priority
 /swap.img file 8388544 0 -2
ProcVersion: Linux version 4.15.0-97-generic (buildd@bos02-ppc64el-006) (gcc version 5.4.0 20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.12)) #98~16.04.1-Ubuntu SMP Tue Apr 7 13:02:13 UTC 2020
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)
cpu_cores: Number of cores present = 20
cpu_coreson: Number of cores online = 19
cpu_dscr: DSCR is 0
cpu_freq:
 min: 3.694 GHz (cpu 159)
 max: 3.695 GHz (cpu 1)
 avg: 3.694 GHz
cpu_runmode:
 Could not retrieve current diagnostics mode,
 No kernel interface to firmware
cpu_smt: SMT=8