dnotify in ubuntu_stress_smoke_test failed on KVM kernels

[Po-Hsu Lin]

== Justification ==
In the Xenial 4.4 and Bionic 4.15 KVM kernel, the CONFIG_DNOTIFY was not set, which is causing failures in the stress-ng dnotify test.

 [stdout] dnotify FAILED
 [stdout] stress-ng: debug: [3043] 2 processors online, 2 processors configured
 [stdout] stress-ng: info: [3043] dispatching hogs: 4 dnotify
 [stdout] stress-ng: debug: [3043] cache allocate: reducing cache level from L3 (too high) to L2
 [stdout] stress-ng: debug: [3043] cache allocate: default cache size: 4096K
 [stdout] stress-ng: debug: [3043] starting stressors
 [stdout] stress-ng: debug: [3044] stress-ng-dnotify: started [3044] (instance 0)
 [stdout] stress-ng: debug: [3043] 4 stressors spawned
 [stdout] stress-ng: fail: [3044] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: debug: [3046] stress-ng-dnotify: started [3046] (instance 2)
 [stdout] stress-ng: debug: [3047] stress-ng-dnotify: started [3047] (instance 3)
 [stdout] stress-ng: fail: [3044] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3046] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3044] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3046] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3046] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3046] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3046] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] info: 5 failures reached, aborting stress process
 [stdout] stress-ng: debug: [3046] stress-ng-dnotify: exited [3046] (instance 2)
 [stdout] stress-ng: fail: [3047] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3047] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3047] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3047] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3047] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] info: 5 failures reached, aborting stress process
 [stdout] stress-ng: debug: [3047] stress-ng-dnotify: exited [3047] (instance 3)
 [stdout] stress-ng: fail: [3044] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3044] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] info: 5 failures reached, aborting stress process
 [stdout] stress-ng: debug: [3044] stress-ng-dnotify: exited [3044] (instance 0)
 [stdout] stress-ng: error: [3043] process 3044 (stress-ng-dnotify) terminated with an error, exit status=1 (stress-ng core failure)
 [stdout] stress-ng: debug: [3043] process [3044] terminated
 [stdout] stress-ng: debug: [3045] stress-ng-dnotify: started [3045] (instance 1)
 [stdout] stress-ng: fail: [3045] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3045] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3045] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3045] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] stress-ng: fail: [3045] stress-ng-dnotify: fcntl F_NOTIFY failed, errno=22 (Invalid argument)
 [stdout] info: 5 failures reached, aborting stress process
 [stdout] stress-ng: debug: [3045] stress-ng-dnotify: exited [3045] (instance 1)
 [stdout] stress-ng: error: [3043] process 3045 (stress-ng-dnotify) terminated with an error, exit status=1 (stress-ng core failure)
 [stdout] stress-ng: debug: [3043] process [3045] terminated
 [stdout] stress-ng: error: [3043] process 3046 (stress-ng-dnotify) terminated with an error, exit status=1 (stress-ng core failure)
 [stdout] stress-ng: debug: [3043] process [3046] terminated
 [stdout] stress-ng: error: [3043] process 3047 (stress-ng-dnotify) terminated with an error, exit status=1 (stress-ng core failure)
 [stdout] stress-ng: debug: [3043] process [3047] terminated
 [stdout] stress-ng: info: [3043] unsuccessful run completed in 0.01s

== Fix ==
UBUNTU: kvm: [Config] enable CONFIG_DNOTIFY

== Test ==
The dnotify test in stress-ng will pass with this patch applied.
Test kernel could be found here:
http://people.canonical.com/~phlin/kernel/lp-1782723-dnotify/

== Regression Potential ==
Minimal.
No code changes, just a config change.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-1016-kvm 4.15.0-1016.16
ProcVersionSignature: User Name 4.15.0-1016.16-kvm 4.15.18
Uname: Linux 4.15.0-1016-kvm x86_64
ApportVersion: 2.20.9-0ubuntu7.3
Architecture: amd64
Date: Fri Jul 20 08:11:19 2018
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-kvm
UpgradeStatus: No upgrade log present (probably fresh install)

[Colin Ian King (colin-king)]

This also occurs in 4.15.0-1012-kvm so it is NOT a regression.

Config has:

# CONFIG_DNOTIFY is not set

so the failure is because DNOTIFY has be disables, which I believe is an issue, this functionality should be enabled IMHO.

[Po-Hsu Lin (cypressyew)]

Affecting X-KVM as well.

[Po-Hsu Lin (cypressyew)]

Task for Linux set to won't fix as per Kamal's comment[1]:
    Since dnotify has been obsolete for many years now, we would prefer not
to enable it in linux-kvm (if its only for the purpose of stress-ng
testing).

This will be addressed in the test suite instead.

[1] https://lists.ubuntu.com/archives/kernel-team/2018-August/094737.html

[Po-Hsu Lin (cypressyew)]

dnotify test will now get skipped for KVM kernels.
http://kernel.ubuntu.com/git/ubuntu/autotest-client-tests.git/commit/?id=f0dde6e357b4d87f7509c6a8105457fff9619a78