Comment 0 for bug 1809699

This test will always return PASSED even if there are some failures there, commit 8fe6e53a8ed5f0 can fix this issue:

$ sudo make -C linux/tools/testing/selftests TARGETS=cpu-hotplug run_tests
make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests'
for TARGET in cpu-hotplug; do \
 make -C $TARGET; \
done;
make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/cpu-hotplug'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/cpu-hotplug'
for TARGET in cpu-hotplug; do \
 make -C $TARGET run_tests; \
done;
make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/cpu-hotplug'
pid 25001's current affinity mask: 3
pid 25001's new affinity mask: 1
CPU online/offline summary:
  Cpus in online state: 0-1
  Cpus in offline state: 2
Limited scope test: one hotplug cpu
  (leaves cpu in the original state):
  online to offline to online: cpu 1
  offline to online to offline: cpu 2
./cpu-on-off-test.sh: line 78: /sys/devices/system/cpu/cpu2/online: No such file or directory
online_cpu_expect_success 2: unexpected fail
./cpu-on-off-test.sh: line 83: /sys/devices/system/cpu/cpu2/online: No such file or directory
offline_cpu_expect_success 2: unexpected fail
selftests: cpu-on-off-test.sh [PASS]
make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/cpu-hotplug'
make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests'

For Trusty, it's missing another 20 commits to reach 8fe6e53:
4813d2e736 (tools: memory-hotplug fix unexpected operator error)
ddddda9bc4 (tools: selftests - create a separate hotplug target for full range test)
a88cc108f6 (lib: Export interval_tree)
93e9ef83f4 (test: add minimal module for verification testing)
3e2a4c183a (test: check copy_to/from_user boundary validation)
64a8946b44 (net: filter: BPF testsuite)
7069a97a14 (selftests/net: move test out of Makefile into a shell script)
3c25fa14f0 (selftests/user: move test out of Makefile into a shell script)
24fe831c17 (tools/testing/selftests/sysctl: validate sysctl_writes_strict)
0a8adf5847 (test: add firmware_class loader test)
6e68e6c5e4 (ftracetest: Initial commit for ftracetest)
4f5ce5e8d7 (selftests: add memfd_create() + sealing tests)
c9b26b81af (syscalls: add selftest for execveat(2))
3ce51050fa (selftest: size: Add size test for Linux kernel) backport with context arrangement
87b2d44026 (selftests: add memfd/sealing page-pinning tests)
498b473af9 (tools: selftests: fix build issue with make kselftests target)
ce6a144a0d (selftests/memfd: Run test on all architectures)
5e29a9105b (selftests: Introduce minimal shared logic for running tests)
cc16782169 (selftests: change cpu on-off-test.sh name to be unique)
8c749ce93e (selftests: create test-specific kconfig fragments)
8fe6e53a8e (selftests/cpu-hotplug: exit with failure when test occured unexpected behaviors)

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-141-generic 4.4.0-141.167
ProcVersionSignature: Ubuntu 4.4.0-141.167-generic 4.4.162
Uname: Linux 4.4.0-141-generic s390x
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
AlsaDevices: Error: command ['ls', '-l', '/dev/snd/'] failed with exit code 2: ls: cannot access '/dev/snd/': No such file or directory
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: s390x
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
CurrentDmesg:

Date: Mon Dec 24 04:08:18 2018
HibernationDevice: RESUME=UUID=ca468a9c-9563-442c-85c6-6055e800a66e
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
Lspci:

Lsusb: Error: command ['lsusb'] failed with exit code 1:
PciMultimedia:

ProcFB: Error: [Errno 2] No such file or directory: '/proc/fb'
ProcKernelCmdLine: root=UUID=b65b756a-ba4e-4c53-aa32-0db2bdb50bb3 crashkernel=196M
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-141-generic N/A
 linux-backports-modules-4.4.0-141-generic N/A
 linux-firmware 1.157.21
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)