[PATCH] libbpf: fix readelf output parsing on powerpc with recent binutils

[Justin Forbes]

On Mon, Dec 2, 2019 at 3:37 AM Daniel Borkmann <daniel at iogearbox.net> wrote:
>
> On Mon, Dec 02, 2019 at 04:53:26PM +1100, Michael Ellerman wrote:
> > Aurelien Jarno <aurelien at aurel32.net> writes:
> > > On powerpc with recent versions of binutils, readelf outputs an extra
> > > field when dumping the symbols of an object file. For example:
> > >
> > >     35: 0000000000000838    96 FUNC    LOCAL  DEFAULT [<localentry>: 8]     1 btf_is_struct
> > >
> > > The extra "[<localentry>: 8]" prevents the GLOBAL_SYM_COUNT variable to
> > > be computed correctly and causes the checkabi target to fail.
> > >
> > > Fix that by looking for the symbol name in the last field instead of the
> > > 8th one. This way it should also cope with future extra fields.
> > >
> > > Signed-off-by: Aurelien Jarno <aurelien at aurel32.net>
> > > ---
> > >  tools/lib/bpf/Makefile | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > Thanks for fixing that, it's been on my very long list of test failures
> > for a while.
> >
> > Tested-by: Michael Ellerman <mpe at ellerman.id.au>
>
> Looks good & also continues to work on x86. Applied, thanks!

This actually seems to break horribly on PPC64le with binutils 2.33.1
resulting in:
Warning: Num of global symbols in sharedobjs/libbpf-in.o (32) does NOT
match with num of versioned symbols in libbpf.so (184). Please make
sure all LIBBPF_API symbols are versioned in libbpf.map.

This is the only arch that fails, with x86/arm/aarch64/s390 all
building fine.  Reverting this patch allows successful build across
all arches.

Justin