ACK/cmt: [SRU][focal/linux-riscv-5.8][PATCH 0/1] gcc version used for kernel configs doesn't match the one used for builds

[Juerg Haefliger]

On Mon, 28 Jun 2021 18:31:24 +0200
Kleber Sacilotto de Souza <kleber.souza at canonical.com> wrote:

> BugLink: https://bugs.launchpad.net/bugs/1933856
> 
> [Impact]
> linux-riscv-5.8 needs to be built with gcc-10 in Focal otherwise it won't boot.
> This was fixed by commit "UBUNTU: [Packaging] Use gcc-10 for riscv 5.8 kernel
> build", which adds gcc-10 as "Build-Depends-Arch" and sets a variable "gcc" in
> 'debian/rules', which is passed down to make by
> 'debian/rules.d/2-binary-arch.mk'.
> 
> The other gcc version dependency is when we generate locally the kernel configs
> by running 'make syncconfig', which is called by
> 'debian/scripts/misc/kernelconfig'. Currently, the syncconfig is called using
> the chroot default compiler, which in Focal is gcc-9. So far there hasn't been
> any major differences, however with the update of gcc-10 in Groovy and Focal
> from 10.2.0 to 10.3.0 some KASAN related config options are not available
> anymore, causing some changes on the configs generated. The problem with
> non-matching gcc versions being used, is that there will be a mismatch between
> the configs being generated during the preparation of the kernel and the ones
> during the build.

Differences as in CC_VERSION is different or are there other config
differences?

 
> [Fix]
> The proposed fix is to use the same variable defined for the build, passing it
> down to 'debian/scripts/misc/kernelconfig' and using it to define the correct
> cross-compiler to be used.
> 
> [Where problems could occur]
> If the environment variables are not set correctly the build can break in some
> environment which was not tested.
> 
> Kleber Sacilotto de Souza (1):
>   UBUNTU: [Packaging] Use gcc-10 for riscv-5.8 kernel configs
> 
>  debian/rules.d/1-maintainer.mk   | 4 ++--
>  debian/scripts/misc/kernelconfig | 7 ++++---
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 

We're deviating from other kernels. Shouldn't this be a cranky fix of sorts
or is there a reason why we can't put this in all kernels?

Acked-by: Juerg Haefliger <juergh at canonical.com>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20210629/1c4aaa1d/attachment-0001.sig>