kfunc use newbie question

[Jiri Pirko <jiri@resnulli.us>]

Hi BPF :)

I'm trying to use bpf_dynptr_from_skb() kfunc in my program. I compiled
it with having following declaration in the bpf .c file:
extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags,
                               struct bpf_dynptr *ptr__uninit) __ksym;

I have all "BPF/BTF" kernel config options on. During load,
I'm still getting:

libbpf: failed to find BTF for extern 'bpf_dynptr_from_skb': -3

I'm pretty much clueless about what may be wrong. Documentation didn't
help me either :/

Any idea what I may be doing wrong?

Thanks

Jiri