Subject: Re: linux-next: new objtool warnings

From: Nathan Chancellor <[email-masked]>
Date: Wed, 5 Nov 2025 13:09:23 -0700

On Wed, Nov 05, 2025 at 08:16:13PM +0100, Peter Zijlstra wrote:
> # make O=tmp-build clean
> # make O=tmp-build allmodconfig
> # make O=tmp-build -j64 vmlinux 2>&1 | grep "\[M\]"
>   CC [M]  sound/sound_core.o
>   CC [M]  virt/lib/irqbypass.o
>   AS [M]  arch/x86/crypto/twofish-x86_64-asm_64.o
>   CC [M]  arch/x86/crypto/twofish_glue.o
>   CC [M]  samples/vfio-mdev/mtty.o
>   CC [M]  sound/ac97_bus.o
>   AS [M]  arch/x86/crypto/twofish-x86_64-asm_64-3way.o
>   CC [M]  arch/x86/crypto/twofish_glue_3way.o

Thanks, I bisected this to commit d2d5cba5d92c ("kbuild: remove EXPERT
and !COMPILE_TEST guarding from TRIM_UNUSED_KSYMS"), which explains
everything when looking at Makefile:

  ifdef CONFIG_TRIM_UNUSED_KSYMS
  # For the kernel to actually contain only the needed exported symbols,
  # we have to build modules as well to determine what those symbols are.
  KBUILD_MODULES := y
  endif

Maybe we want to restore the !COMPILE_TEST dependency?

Cheers,
Nathan