On Wed, Jul 29, 2020 at 10:51:26AM -0700, Andrii Nakryiko wrote: > On Wed, Jul 29, 2020 at 9:04 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > On Tue, Jul 28, 2020 at 04:35:16PM -0700, Andrii Nakryiko wrote: > > > > SNIP > > > > > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > > > > index bae557ff2da8..c981e258fed3 100644 > > > > --- a/include/linux/bpf.h > > > > +++ b/include/linux/bpf.h > > > > @@ -1306,6 +1306,8 @@ int btf_struct_access(struct bpf_verifier_log *log, > > > > const struct btf_type *t, int off, int size, > > > > enum bpf_access_type atype, > > > > u32 *next_btf_id); > > > > +bool btf_struct_ids_match(struct bpf_verifier_log *log, > > > > + int off, u32 id, u32 mid); > > > > int btf_resolve_helper_id(struct bpf_verifier_log *log, > > > > const struct bpf_func_proto *fn, int); > > > > > > > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > > > > index 1ab5fd5bf992..562d4453fad3 100644 > > > > --- a/kernel/bpf/btf.c > > > > +++ b/kernel/bpf/btf.c > > > > @@ -4140,6 +4140,35 @@ int btf_struct_access(struct bpf_verifier_log *log, > > > > return -EINVAL; > > > > } > > > > > > > > +bool btf_struct_ids_match(struct bpf_verifier_log *log, > > > > + int off, u32 id, u32 mid) > > just realized that if id == mid and off == 0, btf_struct_ids_match() > will return false. Right now verifier is careful to not call > btf_struct_ids_match in such case, but I wonder if it's better to make > that (common) case also work? right, also we should call btf_struct_ids_match when IDs are equal and off != 0, which we don't do now jirka
