Re: [PATCH v2 1/3] vmlinux.lds.h: Add .gnu.version* to DISCARDS

[Fangrui Song]

On 2020-06-22, Kees Cook wrote:
> For vmlinux linking, no architecture uses the .gnu.version* section,
> so remove it via the common DISCARDS macro in preparation for adding
> --orphan-handling=warn more widely.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> include/asm-generic/vmlinux.lds.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index db600ef218d7..6fbe9ed10cdb 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -934,6 +934,7 @@
> 	*(.discard)							\
> 	*(.discard.*)							\
> 	*(.modinfo)							\
> +	*(.gnu.version*)						\
> 	}
>
> /**
> --
> 2.25.1

I wonder what lead to .gnu.version{,_d,_r} sections in the kernel.

tools/lib/bpf/libbpf_internal.h uses `.symver` directive and
-Wl,--version-script, which may lead to .gnu.version{,_d}, but this only
applies to the userspace libbpf.so

libperf.so has a similar -Wl,--version-script.

Linking vmlinux does not appear to use any symbol versioning.