Re: [PATCH dwarves v3 0/2] btf: support BTF_KIND_ENUM64

[Jiri Olsa <olsajiri@gmail.com>]

On Mon, Jul 11, 2022 at 11:16:21AM +0200, Jiri Olsa wrote:
> On Wed, Jun 29, 2022 at 06:44:52PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Wed, Jun 29, 2022 at 12:12:13AM -0700, Yonghong Song escreveu:
> > > Add support for enum64. For 64-bit enumerator value,
> > > previously, the value is truncated into 32bit, e.g.,
> > > for the following enum in linux uapi bpf.h,
> > >   enum {
> > >         BPF_F_INDEX_MASK                = 0xffffffffULL,
> > >         BPF_F_CURRENT_CPU               = BPF_F_INDEX_MASK,
> > >   /* BPF_FUNC_perf_event_output for sk_buff input context. */
> > >         BPF_F_CTXLEN_MASK               = (0xfffffULL << 32),
> > >   };    
> > 
> > Applied, added the entry for skip generating enums to the man page,
> > added support to the pahole BTF loader, used the new pahole to build
> > bpf-next/master, all seems ok, pushing to next on git.kernel.org so that
> > the libbpf github CI can give it a go.
> > 
> > To build with torvalds/master one has to add --skip_encoding_btf_enum64,
> > I think, haven't tested with it, without it isn't working, libbpf
> > complains at that btfids tool.
> > 
> > Please check/test what is in there now:
> > 
> >   git://git.kernel.org/pub/scm/devel/pahole/pahole.git next
> >   https://git.kernel.org/pub/scm/devel/pahole/pahole.git/log/?h=next
> > 
> > Unless someone screams I plan pushing out a new release, update fedora
> > packages, etc early next week its overdue by now.
> 
> I used this new pahole in kernel build and it looks ok,
> but I'm getting following warning:
> 
>   BTFIDS  vmlinux
> WARN: resolve_btfids: unresolved symbol mptcp_sock
> 
> might be specific to my .config, I'll check and let you know

ok I have only FWD declaration of mptcp_sock struct, that's why it
can't get resolved.. when I enabled CONFIG_MPTCP it goes away

so no problem with pahole ;-)

Tested-by: Jiri Olsa <jolsa@kernel.org>


the problem is with the btf_sock_ids array that carries mptcp_sock
BTF id even when the CONFIG_MPTCP option is not enabled

I'll follow up on that in separate email

thanks,
jirka