Re: [PATCH 04/16] net: bpfilter: use 'userprogs' syntax to build bpfilter_umh

Michal Kubecek
2020-06-08T11:56:35Z

On Thu, Apr 23, 2020 at 04:39:17PM +0900, Masahiro Yamada wrote:
> The user mode helper should be compiled for the same architecture as
> the kernel.
>
> This Makefile reuses the 'hostprogs' syntax by overriding HOSTCC with CC.
>
> Now that Kbuild provides the syntax 'userprogs', use it to fix the
> Makefile mess.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> Reported-by: kbuild test robot <lkp@intel.com>
> ---
>
> net/bpfilter/Makefile | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
> index 36580301da70..6ee650c6badb 100644
> --- a/net/bpfilter/Makefile
> +++ b/net/bpfilter/Makefile
> @@ -3,17 +3,14 @@
> # Makefile for the Linux BPFILTER layer.
> #
>
> -hostprogs := bpfilter_umh
> +userprogs := bpfilter_umh
> bpfilter_umh-objs := main.o
> -KBUILD_HOSTCFLAGS += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
> -HOSTCC := $(CC)
> +user-ccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
>
> -ifeq ($(CONFIG_BPFILTER_UMH), y)
> -# builtin bpfilter_umh should be compiled with -static
> +# builtin bpfilter_umh should be linked with -static
> # since rootfs isn't mounted at the time of __init
> # function is called and do_execv won't find elf interpreter
> -KBUILD_HOSTLDFLAGS += -static
> -endif
> +bpfilter_umh-ldflags += -static
>
> $(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh

Hello,

I just noticed that this patch (now in mainline as commit 8a2cc0505cc4)
drops the test if CONFIG_BPFILTER_UMH is "y" so that -static is now
passed to the linker even if bpfilter_umh is built as a module which
wasn't the case in v5.7.

This is not mentioned in the commit message and the comment still says
"*builtin* bpfilter_umh should be linked with -static" so this change
doesn't seem to be intentional. Did I miss something?

Michal Kubecek