ubuntu_nbd_smoke test failed - Cannot unload Network Block Device module nbd.o X-4.15

[Sean Feole]

Xenial 4.15, appears to only occur on a few Instances.

BM.DenseIO2.52
BM.Standard1.36
VM.Standard2.24

01/25 08:22:11 DEBUG| parallel:0037| Filesystem 1K-blocks Used Available Use% Mounted on
01/25 08:22:11 DEBUG| parallel:0037| /dev/nbd0 122835 103951 9710 92% /mnt/nbd-test-12329
01/25 08:22:11 DEBUG| parallel:0037|
01/25 08:22:11 DEBUG| parallel:0037| removing file /mnt/nbd-test-12329/largefile
01/25 08:22:11 DEBUG| parallel:0037| unmounting /mnt/nbd-test-12329
01/25 08:22:11 DEBUG| parallel:0037| stopping client
01/25 08:22:11 DEBUG| parallel:0037| disconnect, sock, done
01/25 08:22:11 DEBUG| parallel:0037| killing server
01/25 08:22:11 DEBUG| parallel:0037| ================================================================================
01/25 08:22:11 DEBUG| parallel:0037| Cannot unload Network Block Device module nbd.o
01/25 08:22:11 DEBUG| parallel:0037| stderr:
01/25 08:22:11 DEBUG| parallel:0037| bs=1024, sz=134217728 bytes
01/25 08:22:11 DEBUG| parallel:0037| timeout=30
01/25 08:22:11 DEBUG| parallel:0037| e2fsck 1.42.13 (17-May-2015)
01/25 08:22:11 DEBUG| parallel:0037| modprobe: FATAL: Module nbd is in use.
01/25 08:22:12 INFO | job:0215| ERROR ubuntu_nbd_smoke_test.nbd-smoke-test ubuntu_nbd_smoke_test.nbd-smoke-test timestamp=1548404532 localtime=Jan 25 08:22:12 Command </home/ubuntu/autotest/client/tests/ubuntu_nbd_smoke_test/ubuntu_nbd_smoke_test.sh> failed, rc=1, Command returned non-zero exit status
  * Command:
      /home/ubuntu/autotest/client/tests/ubuntu_nbd_smoke_test/ubuntu_nbd_smoke
      _test.sh
  Exit status: 1
  Duration: 6.25446605682

[Kleber Sacilotto de Souza (kleber-souza)]

Having the same flakiness with bionic/linux 4.15.0-166.174 running on aws a1.medium.

[Po-Hsu Lin (cypressyew)]

Found on B-AWS 4.15.0-1118.125 on a1.medium only

[Po-Hsu Lin (cypressyew)]

UBUNTU: SAUCE: ubuntu_nbd_smoke_test: wait before removing the module
https://git.launchpad.net/~canonical-kernel-team/+git/autotest-client-tests/commit/?id=1edbf63ac052bc3d37384901f70c0366dca249e3

[Po-Hsu Lin (cypressyew)]

Mark this as fix-committed, will flip this to fix-released after this cycle.