Re: [mainline]Error while running make modules_install command

[Omar Sandoval <osandov@osandov.com>]

On Tue, Nov 04, 2025 at 05:56:03PM -0700, Nathan Chancellor wrote:
> + Nicolas and Alexey, just as an FYI.
> 
> Top of thread is:
> 
> https://lore.kernel.org/7fef7507-ad64-4e51-9bb8-c9fb6532e51e@linux.ibm.com/
> 
> On Tue, Nov 04, 2025 at 04:54:38PM +0530, Venkat Rao Bagalkote wrote:
> > IBM CI has also reported this error.
> > 
> > 
> > Error:
> > 
> > 
> > depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname
> > prefix
> >   INSTALL /boot
> > depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname
> > prefix
> > depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname
> > prefix
> > 
> > 
> > Git bisect is pointing to below commit as first bad commit.
> > 
> > 
> > d50f21091358b2b29dc06c2061106cdb0f030d03 is the first bad commit
> > commit d50f21091358b2b29dc06c2061106cdb0f030d03
> > Author: Dimitri John Ledkov <dimitri.ledkov@surgut.co.uk>
> > Date:   Sun Oct 26 20:21:00 2025 +0000
> > 
> >     kbuild: align modinfo section for Secureboot Authenticode EDK2 compat
> 
> Thank you for the bisect. I can reproduce this with at least kmod 29.1,
> which is the version I can see failing in drgn's CI from Ubuntu Jammy
> (but I did not see it with kmod 34, which is the latest version in Arch
> Linux at the moment).
> 
> Could you and Omar verify if the following diff resolves the error for
> you? I think this would allow us to keep Dimitri's fix for the
> Authenticode EDK2 calculation (i.e., the alignment) while keeping kmod
> happy. builtin.modules.modinfo is the same after this diff as it was
> before Dimitri's change for me.
> 
> Cheers,
> Nathan
> 
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index ced4379550d7..c3f135350d7e 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -102,11 +102,23 @@ vmlinux: vmlinux.unstripped FORCE
>  # modules.builtin.modinfo
>  # ---------------------------------------------------------------------------
>  
> +# .modinfo in vmlinux is aligned to 8 bytes for compatibility with tools that
> +# expect sufficiently aligned sections but the additional NULL bytes used for
> +# padding to satisfy this requirement break certain versions of kmod with
> +#
> +#   depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix
> +#
> +# Strip the trailing padding bytes after extracting the .modinfo sections to
> +# comply with what kmod expects to parse.
> +quiet_cmd_modules_builtin_modinfo = GEN     $@
> +      cmd_modules_builtin_modinfo = $(cmd_objcopy); \
> +                                    sed -i 's/\x00\+$$/\x00/g' $@
> +
>  OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
>  
>  targets += modules.builtin.modinfo
>  modules.builtin.modinfo: vmlinux.unstripped FORCE
> -	$(call if_changed,objcopy)
> +	$(call if_changed,modules_builtin_modinfo)
>  
>  # modules.builtin
>  # ---------------------------------------------------------------------------

Thanks for the quick fix, this worked for me on a machine with kmod
version 28.

Tested-by: Omar Sandoval <osandov@fb.com>

Thanks,
Omar