On Thu, Sep 19, 2024 at 4:05 AM Tao Chen <chen.dylane@xxxxxxxxx> wrote:
>
> 在 2024/9/14 23:40, Tao Chen 写道:
> > The commit "5902da6d8a52" set expected_attach_type again with
> > field of bpf_program after libpf_prepare_prog_load, which makes
> > expected_attach_type = 0 no sense when kenrel not support the
> > attach_type feature, so fix it.
> >
> > Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt")
> > Suggested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> > ---
> > tools/lib/bpf/libbpf.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > Change list:
> > - v2 -> v3:
> > - update BPF_TRACE_UPROBE_MULTI both in prog and opts suggedted by
> > Andrri
> > - v1 -> v2:
> > - restore the original initialization way suggested by Jiri
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 219facd0e66e..a78e24ff354b 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -7352,8 +7352,14 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog,
> > opts->prog_flags |= BPF_F_XDP_HAS_FRAGS;
> >
> > /* special check for usdt to use uprobe_multi link */
> > - if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK))
> > + if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) {
> > + /* for BPF_TRACE_KPROBE_MULTI, user might want to query exected_attach_type
> > + * in prog, and expected_attach_type we set in kenrel is from opts, so we
> > + * update both.
> > + */
> > prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI;
> > + opts->expected_attach_type = BPF_TRACE_UPROBE_MULTI;
> > + }
> >
> > if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) {
> > int btf_obj_fd = 0, btf_type_id = 0, err;
> > @@ -7443,6 +7449,7 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
> > load_attr.attach_btf_id = prog->attach_btf_id;
> > load_attr.kern_version = kern_version;
> > load_attr.prog_ifindex = prog->prog_ifindex;
> > + load_attr.expected_attach_type = prog->expected_attach_type;
> >
> > /* specify func_info/line_info only if kernel supports them */
> > if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) {
> > @@ -7474,9 +7481,6 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
> > insns_cnt = prog->insns_cnt;
> > }
> >
> > - /* allow prog_prepare_load_fn to change expected_attach_type */
> > - load_attr.expected_attach_type = prog->expected_attach_type;
> > -
> > if (obj->gen_loader) {
> > bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name,
> > license, insns, insns_cnt, &load_attr,
>
> Hi, guys, please review this patch again, the previous versions:
It looks good, but bpf-next is closed right now due to merge window.
I'll apply when the tree is open again.
> v1:
> https://lore.kernel.org/bpf/20240913121627.153898-1-chen.dylane@xxxxxxxxx/
> v2:
> https://lore.kernel.org/bpf/20240913164355.176021-1-chen.dylane@xxxxxxxxx/
>
> --
> Best Regards
> Dylane Chen
