Building libafl_qemu/qemu_systemmode fuzzer in the Docker container

[vringar]

Hey everyone,

I'm trying to get started in fuzzing with qemu_systemmode and am currently struggling with setting up a build environment.
When building and running the Dockerfile with docker build -t libafl . && docker run --rm -it -- "cd fuzzers/qemu_systemmode" I encounter errors of the following shape:

error[E0308]: arguments to this function are incorrect
    --> /libafl/libafl_qemu/src/emu.rs:1424:23
     |
1424 |             let num = libafl_qemu_sys::libafl_add_edge_hook(gen, exec, data);
     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |
note: expected unsafe fn, found normal fn
    --> /libafl/libafl_qemu/src/emu.rs:1424:61
     |
1424 |             let num = libafl_qemu_sys::libafl_add_edge_hook(gen, exec, data);
     |                                                             ^^^
     = note: expected enum `std::option::Option<unsafe extern "C" fn(_, _, _) -> _>`
                found enum `std::option::Option<extern "C" fn(_, _, _) -> _>`

indicating that bindgen generated something as an unsafe fn but the code expects a regular fn
I then saw the qemu_fuzzers CI job and tried to emulate its setup builds the same code successfully.

So I changed the LLVM version back to 17, set the toolchain to stable, installed all dependencies and set all environment variables. However, the build still keeps failing with the same error message.

My checklist for further reference:

• rustup default stable
• run all rustup commands (copy from here
• cargo install ucd-generate cargo-make wasm-pack
• install deps (copy from here
• apt install python3-pip && pip3 install --break-system-packages msgpack jinja2 find_libpython
• export MAKEFLAGS="-j$(expr $(nproc) \+ 1)"
• apt-get install chromium

Any pointers, or even the confirmation that this is not just an issue for me would be greatly appreciated.

PS: I had a patch that I had to revert because it broke the qemu_fuzzers CI job but made my local build pass. However, I'd like to avoid carrying a patch on top of LibAFL and also don't feel confident that this fixes the underlying issue.