Trigger feedback side effects during force-loading

[Andrew-Fryer]

During some experimentation, I noticed that calling load_initial_inputs_forced rather than load_initial_inputs made a significant impact on the code coverage of my fuzzer.
This was because load_initial_inputs_forced does not evaluate feedbacks (or objectives), so the code coverage of the initial corpus elements wasn't recorded.
While this might be seem significant for very long running fuzzing sessions, it means that other inputs will be added to the corpus that wouldn't otherwise be interesting (because their code coverage is included in the initial corpus elements).

Therefore, I believe that the correct behaviour of load_initial_inputs_forced is to trigger the side-effects of feedbacks and objectives, but then consider the inputs interesting (and not solutions). Alternatively, we could change how feedbacks are implemented not to use side-effects this way.

Please let me know if I'm missing something here!

[tokatoka]

for me, looks good

[domenukk]

+1, thanks.

The Introspection branch needs a fix:

error[E0308]: mismatched types
   --> libafl/src/fuzzer/mod.rs:529:78
    |
529 |             .is_interesting_introspection(state, manager, &input, observers, exit_kind)?;
    |              ----------------------------                                    ^^^^^^^^^ expected `&ExitKind`, found `ExitKind`
    |              |
    |              arguments to this method are incorrect
    |
note: method defined here
   --> libafl/src/feedbacks/mod.rs:79:8
    |
79  |     fn is_interesting_introspection<EM, OT>(
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
85  |         exit_kind: &ExitKind,
    |         --------------------
help: consider borrowing here
    |
529 |             .is_interesting_introspection(state, manager, &input, observers, &exit_kind)?;
    |                                                                              +

[Andrew-Fryer]

Sorry, (I should have noticed that.)

I just built an example fuzzer (forkserver_simple) with introspection on (libafl = { path = "../../libafl/", features = ["std", "derive", "introspection"] }) and it builds now.

[domenukk]

Great, thanks! :)