Re: [PATCH] kbuild: only clean objtool on mrproper

[Michal Suchánek]

On Wed, Feb 25, 2026 at 02:21:05PM -0700, Nathan Chancellor wrote:
> On Wed, Feb 25, 2026 at 09:23:09PM +0100, Michal Suchánek wrote:
> > On Wed, Feb 25, 2026 at 01:04:17PM -0700, Nathan Chancellor wrote:
> > > Wouldn't resolve_btfids need the same treatment?
> > 
> > No, make clean runs the clean target for resolve_btfids but the tool
> > remains.
> 
> That does not reproduce for me personally:
> 
>   $ cat kernel/configs/btf.config
>   CONFIG_BPF_SYSCALL=y
>   # CONFIG_DEBUG_INFO_NONE is not set
>   CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
>   CONFIG_DEBUG_INFO_BTF=y
> 
>   $ make -skj"$(nproc)" ARCH=x86_64 O=build mrproper defconfig btf.config prepare
> 
>   $ ls -al build/tools/{bpf/resolve_btfids/resolve_btfids,objtool/objtool}
>   -rwxr-xr-x 1 nathan nathan 2224456 Feb 25 13:33 build/tools/bpf/resolve_btfids/resolve_btfids
>   -rwxr-xr-x 1 nathan nathan 4046296 Feb 25 13:33 build/tools/objtool/objtool
> 
>   $ make -skj"$(nproc)" ARCH=x86_64 O=build clean
> 
>   $ ls -al build/tools/{bpf/resolve_btfids/resolve_btfids,objtool/objtool}
>   "build/tools/bpf/resolve_btfids/resolve_btfids": No such file or directory (os error 2)
>   "build/tools/objtool/objtool": No such file or directory (os error 2)
> 
> I guess resolve_btfids is not strictly required for external module
> builds because vmlinux may not be present and cmd_btf_ko handles that
> gracefully.

Yes, you are right. The reason why this was not a problem with
resolve_btfids is that missing resolve_btfids is not an error. Or
possibly it's not an error when vmlinux is not in a location where the
build can find it.

resolve_btfids should probably also be preserved but it was not reported
as a bug so far because the case when it would be a problem is fairly
unlikely.

Thanks

Michal