On Wed, Jul 01, 2020 at 09:08:45AM -0700, Andrii Nakryiko wrote:
> On Wed, Jul 1, 2020 at 8:02 AM Alexei Starovoitov
> <alexei.starovoitov@xxxxxxxxx> wrote:
> >
> > On Tue, Jun 30, 2020 at 11:46 PM Andrii Nakryiko <andriin@xxxxxx> wrote:
> > >
> > > Fix bpftool logic of stripping away const/volatile modifiers for all global
> > > variables during BPF skeleton generation. See patch #1 for details on when
> > > existing logic breaks and why it's important. Support special .strip_mods=true
> > > mode in btf_dump. Add selftests validating that everything works as expected.
> >
> > Why bother with the flag?
>
> You mean btf_dump should do this always? That's a bit too invasive a
> change, I don't like it.
>
> > It looks like bugfix to me.
>
> It can be considered a bug fix for bpftool's skeleton generation, but
> it depends on non-trivial changes in libbpf, which are not bug fix per
> se, so should probably better go through bpf-next.
I'm not following.
Without tweaking opts and introducing new flag the actual fix is only
two hunks in patch 1:
@@ -1045,6 +1050,10 @@ static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
stack_start = d->decl_stack_cnt;
for (;;) {
+ t = btf__type_by_id(d->btf, id);
+ if (btf_is_mod(t))
+ goto skip_mod;
+
err = btf_dump_push_decl_stack_id(d, id);
if (err < 0) {
/*
@@ -1056,12 +1065,11 @@ static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
d->decl_stack_cnt = stack_start;
return;
}
-
+skip_mod:
/* VOID */
if (id == 0)
break;
- t = btf__type_by_id(d->btf, id);
