NACK: [SRU][L, K, J, F][M, U][PATCH 1/1] UBUNTU: [Packaging] Expose base (parent) abi for derivatives

[Juerg Haefliger]

Title is misleading, you're not exposing the ABI, just the ABI number.


> BugLink: https://bugs.launchpad.net/bugs/2017006
> 
> This will introduce a new variable UTS_UBUNTU_BASE_RELEASE_ABI equal
> with the parent abi. For backports with multiple inheritance (like
> jammy:linux-aws-5.19) the version from debian.master (kinetic:linux)
> wil be used. In case there is no inheritance, the actual kernel abi
> will be used.
> This will be exposed in <generated/utsrelease.h> so that (dkms)
> modules can use this variable for versioning.
> 
> This is particularly needed in 5.19 kernels, but in anticipation of
> similar usecases, it is best to introduce this in all releases.
> 
> The dkms fix that needs this variable is caused by a commit  that
> broke the interface between the kernel and the lttng-module dkms.
> For other releases, the kernel upstream version was used, but this
> version has stayed the same because 5.19 version is not maintained
> anymore upstream and the commit that broke the interface was fetched
> from the 5.15 stable release.
> We do expose the abi version of the kernel, but it alone will not solve
> this issue because we deliver many derivatives, each with their own
> version. Hence a base main abi version needs to exposed in the
> headers.
> 
> Signed-off-by: Roxana Nicolescu <roxana.nicolescu at canonical.com>
> ---
>  debian/rules.d/0-common-vars.mk | 9 +++++++++
>  debian/rules.d/2-binary-arch.mk | 4 ++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/debian/rules.d/0-common-vars.mk b/debian/rules.d/0-common-vars.mk
> index 1d8f8b85772f..11e202598ee7 100644
> --- a/debian/rules.d/0-common-vars.mk
> +++ b/debian/rules.d/0-common-vars.mk
> @@ -88,6 +88,15 @@ ifneq ($(full_build),false)
>    uploadnum	:= $(uploadnum)-Ubuntu
>  endif
>  
> +# This exposes the base (parent) abi number
> +# For main kernels, this version matches their abi version
> +# Because we may deal with multiple inheritance (jammy:linux-aws-5.19)
> +# we always extract the abi version from debian.master/changelog
> +DEBIAN_BASE_MASTER=debian.master
> +src_base_pkg_name=linux
> +base_revision	:= $(shell sed -n '1s/^$(src_base_pkg_name)\ .*($(release)-\(.*\)).*$$/\1/p' $(DEBIAN_BASE_MASTER)/changelog)
> +base_abinum		:= $(shell echo $(base_revision) | sed -r -e 's/([^\+~]*)\.[^\.]+(~.*)?(\+.*)?$$/\1/')$(abi_suffix)
> +

Yikes.
1) Do we really need to define make variables which are only used in a single
   rule?
2) If make variables then they (base_<foo>) need to be added to the output of
   'printenv' and the definitions should be moved to where the other abinum,
   prev_abinum are defined to keep it all in one place.
3) Defining DEBIAN_BASE_MASTER is pointless.
3) Why hard-code/define the source package name? It's not really needed, is
   it?
4) That sed magic seems overly complicated just to get the abi number...
   Why not use dpkg-parsechangelog to get the version? Look through
   0-common-vars.mk how similar stuff is done elsewhere.
5) $(abi_suffix) was dropped in lunar, please don't reintroduce it.


In hindsight, it might be helpful to define make variables and show them in
printenv for debugging purposes... So I'm not totally opposed to that :-)

...Juerg


>  # XXX: linux-libc-dev got bumped to -803.N inadvertantly by a ti-omap4 upload
>  #      shift our version higher for this package only.  Ensure this only
>  #      occurs for the v2.6.35 kernel so that we do not propogate this into
> diff --git a/debian/rules.d/2-binary-arch.mk b/debian/rules.d/2-binary-arch.mk
> index 6eef2039ec7a..100f3d8e9f7e 100644
> --- a/debian/rules.d/2-binary-arch.mk
> +++ b/debian/rules.d/2-binary-arch.mk
> @@ -335,6 +335,10 @@ endif
>  		"$(hdrdir)/include/generated/compile.h"
>  	# Add UTS_UBUNTU_RELEASE_ABI since UTS_RELEASE is difficult to parse.
>  	echo "#define UTS_UBUNTU_RELEASE_ABI $(abinum)" >> $(hdrdir)/include/generated/utsrelease.h
> +
> +	# Add UTS_UBUNTU_BASE_RELEASE_ABI, needed for dkms modules where we cannot use the upstream version
> +	echo "#define UTS_UBUNTU_BASE_RELEASE_ABI $(base_abinum)" >> $(hdrdir)/include/generated/utsrelease.h
> +
>  	# powerpc kernel arch seems to need some .o files for external module linking. Add them in.
>  ifeq ($(build_arch),powerpc)
>  	mkdir -p $(hdrdir)/arch/powerpc/lib

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