bpf: Resolve modifiers when walking structs

It is impossible to use skb_frag_t in the tracing program. Resolve typedefs
when walking structs.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230626212522.2414485-1-sdf@google.com

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 29fe2109929853dc5d8ecd02e2153c3e2d9b823b..3dd47451f097a04c71057e8943960d571abc466d 100644 (file)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6135,6 +6135,8 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
 
        *flag = 0;
 again:
+       if (btf_type_is_modifier(t))
+               t = btf_type_skip_modifiers(btf, t->type, NULL);
        tname = __btf_name_by_offset(btf, t->name_off);
        if (!btf_type_is_struct(t)) {
                bpf_log(log, "Type '%s' is not a struct\n", tname);