Re: [PATCH] kbuild: use ARCH from compile.h in unclean source tree msg

[David Gow]

On Sat, 3 May 2025 at 01:25, Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
>
> When make finds the source tree unclean, it prints a message to run
> "make ARCH=x86_64 mrproper" message using the ARCH from the command
> line. The ARCH specified in the command line could be different from
> the ARCH of the existing build in the source tree.
>
> This could cause problems in regular kernel build and kunit workflows.
>
> Regular workflow:
>
> - Build x86_64 kernel
>         $ make ARCH=x86_64
> - Try building another arch kernel out of tree with O=
>         $ make ARCH=um O=/linux/build
> - kbuild detects source tree is unclean
>
>   ***
>   *** The source tree is not clean, please run 'make ARCH=um mrproper'
>   *** in /linux/linux_srcdir
>   ***
>
> - Clean source tree as suggested by kbuild
>         $ make ARCH=um mrproper
> - Source clean appears to be clean, but it leaves behind generated header
>   files under arch/x86
>         arch/x86/realmode/rm/pasyms.h
>
> A subsequent x86_64e build fails with
>   "undefined symbol sev_es_trampoline_start referenced ..."
>
> kunit workflow runs into this issue:
>
> - Build x86_64 kernel
> - Run kunit tests:  it tries to build for user specified ARCH or uml
>   as default:
>         $ ./tools/testing/kunit/kunit.py run
>
> - kbuild detects unclean source tree
>
>   ***
>   *** The source tree is not clean, please run 'make ARCH=um mrproper'
>   *** in /linux/linux_6.15
>   ***
>
> - Clean source tree as suggested by kbuild
>         $ make ARCH=um mrproper
> - Source clean appears to be clean, but it leaves behind generated header
>   files under arch/x86
>
> The problem shows when user tries to run tests on ARCH=x86_64:
>
>         $ ./tools/testing/kunit/kunit.py run ARCH=x86_64
>
>         "undefined symbol sev_es_trampoline_start referenced ..."
>
> Build trips on arch/x86/realmode/rm/pasyms.h left behind by a prior
> x86_64 build.
>
> Problems related to partially cleaned source tree are hard to debug.
> Change Makefile to unclean source logic to use ARCH from compile.h
> UTS_MACHINE string. With this change kbuild prints:
>
>         $ ./tools/testing/kunit/kunit.py run
>
>   ***
>   *** The source tree is not clean, please run 'make ARCH=x86_64 mrproper'
>   *** in /linux/linux_6.15
>   ***
>
> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> ---


Thanks very much! This is much better, and has given the right message
on all of the architecture in-/out-of-tree build combinations I've
thrown at it.

Reviewed-by: David Gow <davidgow@xxxxxxxxxx<

Cheers,
-- David

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature