Error with printk and bpf_trace_printk

Hi,

I have a working eBPF program, and I'm trying to add outputs to it.
I'm not able to use both printk and bpf_trace_printk functions. I get
this error:

ELF contains non-map related relo data in entry 0 pointing to section
8! Compiler bug?!

Prog section 'ingress' rejected: Invalid argument (22)!
 - Type:         3
 - Instructions: 16 (0 over limit)
 - License:      GPL

Verifier analysis:

0: (bf) r6 = r1
1: (18) r1 = 0x0
3: (85) call bpf_unspec#0
unknown func bpf_unspec#0

Error fetching program/map!
Failed to retrieve (e)BPF data!

Are there certain "includes" that I need to add?
In addition, I'm not sure I'm using the function correctly. I just
wrote: printk("hi")

Thanks!
Adel