Re: [PATCH] bpftool: Fix version string in recursive builds

[Yonghong Song <yhs@fb.com>]

On 8/14/20 3:17 PM, Ben Hutchings wrote:
> On Fri, 2020-08-14 at 08:43 -0700, Yonghong Song wrote:
> [...]
> > I tried the following
> >
> > --- a/tools/bpf/bpftool/Makefile
> > +++ b/tools/bpf/bpftool/Makefile
> > @@ -25,7 +25,7 @@ endif
> >
> >    LIBBPF = $(LIBBPF_PATH)libbpf.a
> >
> > -BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../..
> > kernelversion)
> > +BPFTOOL_VERSION := $(shell MAKEFLAGS=w make -rR --no-print-directory
> > -sC ../../.. kernelversion)
> >
> > -bash-4.4$ ./bpftool version
> > ./bpftool v5.8.0
> >
> > I set env variable MAKEFLAGS=w, and build bpftool it works fine too.
> > Maybe I miss something or debian changed top level Makefile?
>
> Yes, but we don't change MAKEFLAGS or any of the logic around quietness
> or verbosity.
>
> I assume there are other factors involved, as I've also been unable to
> construct a simple reproducer.

It would be good to know what is the exact problem, and then we can
decide whether this patch is the most appropriate fix or not.

> Ben.
>
> > I am testing against latest bpf tree.
> >
> > >    
> > >    $(LIBBPF): FORCE
> > >    	$(if $(LIBBPF_OUTPUT),@mkdir -p $(LIBBPF_OUTPUT))