[Bug 1866925] [NEW] wrong gcc version for kernel prevents DKMS working

[David Hodgson]

Public bug reported:

Fresh install of minimal LUbuntu 18.04, fully updated (with new kernel).

Install of NVIDIA graphics card drivers from NVIDIA script.

DKMS (needed for re-compile with new kernel versions) fails as the
available gcc is 7.5.0 from 18.04 and the gcc used for compiling the
kernel was 7.4.0 from 18.01.

The gcc for the running kernel is no longer available for installation.

This mismatch is the bug.

There are two alternative solutions:
1. ensure the gcc versions used to compile the available kernels are also available.
2. ensure the kernels are always compiled with the latest available gcc.

The former is probably a better solution as the latter may cause
unnecessary kernel recompiles as the gcc versions change.  The former
may require multiple installed versions of gcc, one for each installed
kernel version, which would need a method of picking the gcc version
which matches the kernel.

It would also be useful if one of the meta-packages ensured that the
installed gcc matches the installed kernel's compiler.

```
$ uname -a
Linux xxxxxx 5.3.0-40-generic #32~18.04.1-Ubuntu SMP Mon Feb 3 14:05:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
```
```
$ lsb_release -rd
Description:	Ubuntu 18.04.4 LTS
Release:	18.04
```

... I'm sorry, but the DKMS make.log with the error has been deleted by
a later re-run attempt for the install.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gcc 4:7.4.0-1ubuntu2.3
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
Date: Tue Mar 10 22:40:51 2020
InstallationDate: Installed on 2020-03-10 (0 days ago)
InstallationMedia: Lubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203)
SourcePackage: gcc-defaults
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: gcc-defaults (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug bionic

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https://bugs.launchpad.net/bugs/1866925

Title:
  wrong gcc version for kernel prevents DKMS working

Status in gcc-defaults package in Ubuntu:
  New

Bug description:
  Fresh install of minimal LUbuntu 18.04, fully updated (with new
  kernel).

  Install of NVIDIA graphics card drivers from NVIDIA script.

  DKMS (needed for re-compile with new kernel versions) fails as the
  available gcc is 7.5.0 from 18.04 and the gcc used for compiling the
  kernel was 7.4.0 from 18.01.

  The gcc for the running kernel is no longer available for
  installation.

  This mismatch is the bug.

  There are two alternative solutions:
  1. ensure the gcc versions used to compile the available kernels are also available.
  2. ensure the kernels are always compiled with the latest available gcc.

  The former is probably a better solution as the latter may cause
  unnecessary kernel recompiles as the gcc versions change.  The former
  may require multiple installed versions of gcc, one for each installed
  kernel version, which would need a method of picking the gcc version
  which matches the kernel.

  It would also be useful if one of the meta-packages ensured that the
  installed gcc matches the installed kernel's compiler.

  ```
  $ uname -a
  Linux xxxxxx 5.3.0-40-generic #32~18.04.1-Ubuntu SMP Mon Feb 3 14:05:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
  ```
  ```
  $ lsb_release -rd
  Description:	Ubuntu 18.04.4 LTS
  Release:	18.04
  ```

  ... I'm sorry, but the DKMS make.log with the error has been deleted
  by a later re-run attempt for the install.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: gcc 4:7.4.0-1ubuntu2.3
  ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
  Uname: Linux 5.3.0-40-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.9-0ubuntu7.9
  Architecture: amd64
  Date: Tue Mar 10 22:40:51 2020
  InstallationDate: Installed on 2020-03-10 (0 days ago)
  InstallationMedia: Lubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203)
  SourcePackage: gcc-defaults
  UpgradeStatus: No upgrade log present (probably fresh install)

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