Re: [PATCH v2 1/2] tools/resolve_btfids: Add --fatal-warnings option

["Thomas Weißschuh" <linux@weissschuh.net>]

On 2024-12-03 14:31:01-0800, Andrii Nakryiko wrote:
> On Tue, Nov 26, 2024 at 1:17 PM Thomas Weißschuh <linux@weissschuh.net> wrote:
> >
> > Currently warnings emitted by resolve_btfids are buried in the build log
> > and are slipping into mainline frequently.
> > Add an option to elevate warnings to hard errors so the CI bots can
> > catch any new warnings.
> >
> > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> > Acked-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/bpf/resolve_btfids/main.c | 12 ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
> > index bd9f960bce3d5b74dc34159b35af1e0b33524d2d..571d29d2da97fea75e5f9c544a95b9ac65f9e579 100644
> > --- a/tools/bpf/resolve_btfids/main.c
> > +++ b/tools/bpf/resolve_btfids/main.c
> > @@ -141,6 +141,7 @@ struct object {
> >  };
> >
> >  static int verbose;
> > +static int warnings;
> >
> >  static int eprintf(int level, int var, const char *fmt, ...)
> >  {
> > @@ -604,6 +605,7 @@ static int symbols_resolve(struct object *obj)
> >                         if (id->id) {
> >                                 pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
> >                                         str, id->id, type_id, id->id);
> > +                               warnings++;
> >                         } else {
> >                                 id->id = type_id;
> >                                 (*nr)--;
> > @@ -625,8 +627,10 @@ static int id_patch(struct object *obj, struct btf_id *id)
> >         int i;
> >
> >         /* For set, set8, id->id may be 0 */
> > -       if (!id->id && !id->is_set && !id->is_set8)
> > +       if (!id->id && !id->is_set && !id->is_set8) {
> >                 pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
> > +               warnings++;
> > +       }
> >
> >         for (i = 0; i < id->addr_cnt; i++) {
> >                 unsigned long addr = id->addr[i];
> > @@ -782,6 +786,7 @@ int main(int argc, const char **argv)
> >                 .funcs    = RB_ROOT,
> >                 .sets     = RB_ROOT,
> >         };
> > +       bool fatal_warnings = false;
> >         struct option btfid_options[] = {
> >                 OPT_INCR('v', "verbose", &verbose,
> >                          "be more verbose (show errors, etc)"),
> > @@ -789,6 +794,8 @@ int main(int argc, const char **argv)
> >                            "BTF data"),
> >                 OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
> >                            "path of file providing base BTF"),
> > +               OPT_BOOLEAN(0, "fatal-warnings", &fatal_warnings,
> > +                           "turn warnings into errors"),
> 
> We are mixing naming styles here: we have "btf_base" with underscore
> separator, and you are adding "fatal-warnings" with dash separator. I
> personally like dashes, but whichever way we should stay consistent.
> So let's fix it, otherwise it looks a bit sloppy.

Ack.

> 
> Please also use [PATCH bpf-next v3] subject prefix to make it explicit
> that this should go through bpf-next tree.

Ack.

> 
> pw-bot: cr
> 
> >                 OPT_END()
> >         };
> >         int err = -1;
> > @@ -823,7 +830,8 @@ int main(int argc, const char **argv)
> >         if (symbols_patch(&obj))
> >                 goto out;
> >
> > -       err = 0;
> > +       if (!(fatal_warnings && warnings))
> > +               err = 0;
> 
> nit: just
> 
> if (!fatal_warnings)
>     err = 0;
> 
> ?

This seems wrong. Now the actual warning counter is never evaluated.
And --fatal_warnings will always lead to an error exit code.

> >  out:
> >         if (obj.efile.elf) {
> >                 elf_end(obj.efile.elf);
> >
> > --
> > 2.47.1
> >