[Pkg-zfsonlinux-devel] Bug#881013: zfs-dkms should depend on matching version of spl-dkms to avoid breakage

[Jason Cohen]

Package: zfs-dkms
Version: 0.7.3-1
Severity: important

Dear Maintainer,

Thank you for the recent zfs/spl 0.7.3-1 upload.  It was greatly appreciated!
However, there appears to be a potential issue with the dependencies of the
zfs-dkms package.  zfs-dkms 0.6.5.11-1 depends on spl-dkms >= 0.6.5.11.  This
is fine when the versions in the repository match, but this is not necessarily
the case. The ZFS kernel modules will not build successfully if SPL and ZFS are
running different versions.

When SPL/ZFS 0.7.3-1 was uploaded to unstable, spl-dkms migrated immediately
but zfs-dkms was delayed as it had to be manually approved from the NEW queue.
Because zfs-dkms 0.6.5.11-1 doesn't depend on the specific matching version of
spl-dkms, but rather will accept a newer version, users on Testing are now
being offered to upgrade to spl-dkms 0.7.3-1, but if they do so, ZFS will break
as DKMS will not be able to build a new ZFS module with the mismatched SPL and
ZFS packages.  At least one user already reported such breakage on Reddit's
/r/debian channel[1].

This situation is likely to continue until Bug #880902 is resolved, as that bug
will prevent zfs-dkms 0.7.3-1 from migrating to testing.

Presumably, this would not have occurred if zfs-dkms 0.6.5.11-1 depended on
spl-dkms=0.6.5.11 rather than >=0.6.5.11.

   * What led up to the situation?

spl-dkms 0.7.3-1 migrated to testing while zfs-dkms 0.7.3-1 did not.  While SPL
and ZFS versions much match to successfully build the ZFS kernel module, zfs-
dkms only requires the same *or higher* version.


   * What exactly did you do (or not do) that was effective (or
     ineffective)?

This can be resolved by holding spl-dkms to 0.6.5.11-1 or manually installing
zfs-dkms 0.7.3-1 from unstable.  My concern is that users may not realize WHY
ZFS has broken.

   * What was the outcome of this action?

The outcome of the spl-dkms upgrade is that ZFS is rendered unuseable unless
one of the mitigations is used.

   * What outcome did you expect instead?

I expected spl-dkms to be held at its current state until the necessary version
of zfs-dkms was available.

[1]:
https://www.reddit.com/r/debian/comments/7b7wy7/does_spl_and_spldkms_have_to_be_the_same_version/



-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (900, 'testing'), (800, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.13.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages zfs-dkms depends on:
ii  debconf [debconf-2.0]  1.5.64
ii  dkms                   2.3-3
ii  lsb-release            9.20170808
ii  spl-dkms               0.7.3-1

Versions of packages zfs-dkms recommends:
ii  zfs-zed         0.7.3-1
ii  zfsutils-linux  0.7.3-1

zfs-dkms suggests no packages.

-- debconf information:
  zfs-dkms/stop-build-for-32bit-kernel: true
* zfs-dkms/note-incompatible-licenses:
  zfs-dkms/stop-build-for-unknown-kernel: true