On Fri, Mar 26, 2021 at 11:59:00AM +0100, Jiri Olsa wrote:

Currently module can be unloaded even if there's a trampoline
register in it. It's easily reproduced by running in parallel:

  # while :; do ./test_progs -t module_attach; done
  # while :; do rmmod bpf_testmod; sleep 0.5; done

Taking the module reference in case the trampoline's ip is
within the module code. Releasing it when the trampoline's
ip is unregistered.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 v3 changes:
   - store module pointer under bpf_trampoline struct

Applied.