[Bug 1828615] Re: v4l2loopback 10.0-1ubuntu1 ADT test failure with linux 5.0.0-14-generic

[Mathew Hodson]

** Changed in: v4l2loopback (Ubuntu)
   Importance: Undecided => Medium

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Title:
  v4l2loopback 10.0-1ubuntu1 ADT test failure with linux
  5.0.0-14-generic

Status in v4l2loopback package in Ubuntu:
  In Progress

Bug description:
  [ Impact ]

  The DKMS package fails to install on kernels based on 5.0;
  specifically noticed in the Bionic HWE Edge kernel.

  [ Test Case ]

  Install the v4l2loopback-dkms package with a 5.0 kernel. The package
  should install without any errors.

  
  [ The Problem ]

  "do_gettimeofday" was deprecated and removed in the 5.0 kernels, so
  the package will not compile since the function it requires does not
  exist.

  [ Proposed Fix ]

  Port the following patch from the package developers which replaces
  calls to the deprecated API with appropriate wrapper functions:
  https://github.com/umlaeute/v4l2loopback/commit/afe0b233070d7ca5d6df83c5f2723d276dcd287d.patch

  [ Testing ]

  I tested this install process (using the .debdiff in comment #1) for
  both 4.15.0-49-generic and 5.0.0-14-generic to test for regressions
  since the changes introduced by this patch are not conditionally
  compiled.

  - Create a Bionic 18.04 VM
  - Install the Bionic Linux HWE Edge kernel from -proposed or install the built .debs located here: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+packages?field.name_filter=linux-hwe-edge&field.status_filter=published&field.series_filter=bionic
  - Try installing v4l2loopback-dkms with apt (or you can pull the sources with "pull-lp-source v4l2loopback bionic" and build with "debuild -b -uc -us"
  - Confirm that installation fails for the 5.0 kernel (it will succeed for 4.15)
  - Pull the sources with "pull-lp-source v4l2loopback bionic"
  - Apply the debdiff "debdiff-apply < path-to-diff-in-this-comment.debdiff"
  - Build the package "debuild -b -uc -us"
  - Install the .deb produced from the previous step "sudo dpkg --install path-to-deb.deb"
  - Verify the installation completed successfully. You can also verify the output of "sudo dkms status" is correct.

  [ Regression Potential ]

  I think regression potential is low if the proposed fix is accepted.
  The function calls that supplant the deprecated ones have been there
  since before kernel 4.15 (of which Bionic is based upon).

      amd64: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/amd64/v/v4l2loopback/20190429_215733_875ac@/log.gz
      arm64: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/arm64/v/v4l2loopback/20190429_220415_875ac@/log.gz
      i386: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/i386/v/v4l2loopback/20190429_215750_875ac@/log.gz
      ppc64el: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/ppc64el/v/v4l2loopback/20190429_215314_875ac@/log.gz
      s390x: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-bionic/bionic/s390x/v/v4l2loopback/20190429_214920_875ac@/log.gz

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