On Tue, Sep 22, 2020 at 11:48 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> On Mon, Sep 21, 2020 at 02:55:27PM -0700, Andrii Nakryiko wrote:
> > On Fri, Sep 18, 2020 at 5:30 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> > >
> > > Currently all the resolve_btfids 'users' are under CONFIG_BPF
> > > code, so if we have CONFIG_BPF disabled, resolve_btfids will
> > > fail, because there's no data to resolve.
> > >
> > > In case CONFIG_BPF is disabled, using resolve_btfids --no-fail
> > > option, that makes resolve_btfids leave quietly if there's no
> > > data to resolve.
> > >
> > > Fixes: c9a0f3b85e09 ("bpf: Resolve BTF IDs in vmlinux image")
> > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > ---
> >
> > If no CONFIG_BTF is specified, there is no need to even run
> > resolve_btfids. So why not do just that -- run resolve_btfids only
> > if both CONFIG_BPF and CONFIG_DEBUG_INFO_BTF are specified?
>
> we can have CONFIG_DEBUG_INFO_BTF without CONFIG_BPF being enabled,
> so we could in theory have in future some BTF ID user outside bpf code,
> but I guess we can enable that, when it actually happens
>
Right. Let's cross that bridge when we get there.
> jirka
>
> >
> >
> > > scripts/link-vmlinux.sh | 9 +++++++--
> > > 1 file changed, 7 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> > > index e6e2d9e5ff48..3173b8cf08cb 100755
> > > --- a/scripts/link-vmlinux.sh
> > > +++ b/scripts/link-vmlinux.sh
> > > @@ -342,8 +342,13 @@ vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
> > >
> > > # fill in BTF IDs
> > > if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
> > > -info BTFIDS vmlinux
> > > -${RESOLVE_BTFIDS} vmlinux
> > > + info BTFIDS vmlinux
> > > + # Let's be more permissive if CONFIG_BPF is disabled
> > > + # and do not fail if there's no data to resolve.
> > > + if [ -z "${CONFIG_BPF}" ]; then
> > > + no_fail=--no-fail
> > > + fi
> > > + ${RESOLVE_BTFIDS} $no_fail vmlinux
> > > fi
> > >
> > > if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
> > > --
> > > 2.26.2
> > >
> >
>
