Build Failure on linux-next (next-20250407)

[Borah, Chaitanya Kumar]

Hello Ard,

Hope you are doing well. I am Chaitanya from the linux graphics team in Intel.

This mail is regarding a build failure we are seeing in our CI runs[1] on linux-next repository.

Since the version next-20250407[2], we are seeing the following build error.

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CALL    scripts/checksyscalls.sh
  DESCEND objtool
  INSTALL libsubcmd_headers
  AS      arch/x86/boot/startup/efi-mixed.o
arch/x86/boot/startup/efi-mixed.o: error: objtool: efi64_stub_entry(): can't find starting instruction
make[3]: *** [scripts/Makefile.build:335: arch/x86/boot/startup/efi-mixed.o] Error 255
make[3]: *** Deleting file 'arch/x86/boot/startup/efi-mixed.o'
make[2]: *** [scripts/Makefile.build:461: arch/x86/boot/startup] Error 2
make[1]: *** [/home/kbuild2/kernel/Makefile:2006: .] Error 2
make: *** [Makefile:248: __sub-make] Error 2
`````````````````````````````````````````````````````````````````````````````````

After bisecting the tree, the following patch [3] seems to be the first "bad" commit

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commit 4f2d1bbc2c92a32fd612e6c3b51832d5c1c3678e
Author: Ard Biesheuvel mailto:ardb@xxxxxxxxxx
Date:   Tue Apr 1 15:34:20 2025 +0200

    x86/boot: Move the EFI mixed mode startup code back under arch/x86, into startup/
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We also verified that if we revert the patch the issue is not seen.

Another observation is that build passes when run on "Ubuntu 20.04", in contrast our CI systems uses "Ubuntu 24.04".

Could you please check why the patch causes this regression and provide a fix if necessary?

Thank you.

Regards

Chaitanya

[1] https://intel-gfx-ci.01.org/tree/linux-next/combined-alt.html?
[2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250407 
[3] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250407&id=4f2d1bbc2c92a32fd612e6c3b51832d5c1c3678e