3.4.2.1. GDB module_init step into it
This is the best method we’ve found so far.
The kernel calls module_init synchronously, therefore it is not hard to step into that call.
As of 4.16, the call happens in do_one_initcall, so we can do in shell 1:
./run
shell 2 after boot finishes (because there are other calls to do_init_module at boot, presumably for the built-in modules):
./run-gdb do_one_initcall
then step until the line:
833 ret = fn();
which does the actual call, and then step into it.
For the next time, you can also put a breakpoint there directly:
./run-gdb init/main.c:833
How we found this out: first we got GDB module_init calculate entry address working, and then we did a bt. AKA cheating :-)