Cannot build nvidia driver via dkms because compiler doesn't match kernel

[Wowbagger]

The kernel installed with 16.04 was built with gcc 5.3.1, but the default compiler installed is 5.4.0 - as such, DKMS refuses to build the nvidia video card driver due to the mismatch. Either build the kernel with the shipping compiler or ship the compiler that was used to build the kernel.

cat /proc/version
Linux version 4.4.0-34-lowlatency (buildd@lgw01-20) (gcc version 5.3.1 20160413 (Ubuntu 5.3.1-14ubuntu2.1) ) #53-Ubuntu SMP PREEMPT Wed Jul 27 19:23:26 UTC 2016
gcc --version
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.1) 5.4.0 20160609
lsb_release -rd
Description: Ubuntu 16.04.1 LTS
Release: 16.04

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: dkms 2.2.0.3-2ubuntu11.1
ProcVersionSignature: Ubuntu 4.4.0-34.53-lowlatency 4.4.15
Uname: Linux 4.4.0-34-lowlatency x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
Date: Mon Aug 1 21:26:15 2016
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: dkms
UpgradeStatus: Upgraded to xenial on 2016-07-23 (9 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Per Heldal (heldal)]

It's not just gcc that has mismatching versions. It's the whole toolchain.

The installed gcc package (according to dpkg) has version 4:5.3.1-1ubuntu1 while the /usr/bin/gcc symlink contained within is pointing to gcc-5.4.0. There is no trace of 5.3.1 binaries on the system, nor are there any available from the repos.

The bug will affect anyone who try to compile and/or link any kernel modules.

[Per Heldal (heldal)]

Seems like alle the dependency-packages are listed as version 5.3.1 (cpp, g++, gcc etc), but the symlinks within links to 5.4.0 binaries. Anyone trying to compile and/or link kernel-modules will have a problem.

[Keith Twombley (ktwombley)]

Would this bug be better addressed if filed under gcc rather than dkms?

Doesn't seem to be dkms's fault that the toolchain installs the wrong version of gcc.

[Per Heldal (heldal)]

When examining repos it seems like the inconsistency was introduced in xenial-updates where packages in the build toolchain was bumped from 5.3.1 to 5.4.0 while the supplied kernel still is built with GCC 5.3.1 and the dependecy-packages that provide symlinks to tool-binaries also remain at version 5.3.1

Package xenial xenial-security xenial-updates
------------------------------------------------------------------------
gcc 4:5.3.1-1ubuntu1
gcc-5 5.3.1-14ubuntu2 5.3.1-14ubuntu2.1 5.4.0-6ubuntu1~16.04.1

The issue of inconsistent versions relates to a number of packages in the chain of build-tools (binaries and libraries) tagged with versions 5.3.1 and/or 5.4.0. DKMS is not to blame.

[Matthias Klose (doko)]

this is not a compiler issue. Apparently you have to build the modules and the kernel with the same version of the compiler, which is now 5.4.x. We usually don't update the dependencies packages, the symlinks stay the same.

[Paul White (paulw2u)]

Further to comment #7, closing Papercuts task.