On Fri, Sep 17, 2021 at 2:57 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> From: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> Given BPF program's BTF perform a linear search through kernel BTFs for
> a possible candidate.
> Then wire the result into bpf_core_apply_relo_insn().
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
> kernel/bpf/btf.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 147 insertions(+), 2 deletions(-)
>
[...]
> + /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
> + spin_lock_bh(&btf_idr_lock);
> + idr_for_each_entry(&btf_idr, mod_btf, id) {
> + if (!btf_is_module(mod_btf))
> + continue;
> + /* linear search could be slow hence unlock/lock
> + * the IDR to avoiding holding it for too long
> + */
> + btf_get(mod_btf);
> + spin_unlock_bh(&btf_idr_lock);
> + err = bpf_core_add_cands(&local_cand, local_essent_len,
> + mod_btf,
> + btf_nr_types(main_btf),
> + cands);
> + if (err)
> + btf_put(mod_btf);
> + goto err_out;
this couldn't have worked properly for modules, missing {} ?
> + spin_lock_bh(&btf_idr_lock);
> + btf_put(mod_btf);
> + }
> + spin_unlock_bh(&btf_idr_lock);
> +
> + return cands;
> +err_out:
> + bpf_core_free_cands(cands);
> + return ERR_PTR(err);
> +}
> +
[...]
