bpf_prog_realloc
struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0);