On Fri, Jun 27, 2014 at 5:05 PM, Alexei Starovoitov [off-list ref] wrote:

eBPF programs are safe run-to-completion functions with load/unload
methods from userspace similar to kernel modules.

User space API:

- load eBPF program
  prog_id = bpf_prog_load(int prog_id, bpf_prog_type, struct nlattr *prog, int len)

  where 'prog' is a sequence of sections (currently TEXT and LICENSE)
  TEXT - array of eBPF instructions
  LICENSE - GPL compatible

+
+       err = -EINVAL;
+       /* look for mandatory license string */
+       if (!tb[BPF_PROG_LICENSE])
+               goto free_attr;
+
+       /* eBPF programs must be GPL compatible */
+       if (!license_is_gpl_compatible(nla_data(tb[BPF_PROG_LICENSE])))
+               goto free_attr;

Seriously?  My mind boggles.

--Andy