en Copyright 2015 Java http://172.16.0.5:8080/history/wasmtime-44.0.1/fuzz/fuzz_targets/call_async.rs#b4ecea38 Add a fuzzer for async wasm (#8440)* Add a fuzzer for async wasmThis commit revives a very old branch of mine to add a fuzzer forWasmtime in async mode. This work was originally blocked onllvm/llvm-project#53891 and while that's still an issue it now containsa workaround for that issue. Support for async fuzzing required a gooddeal of refactorings and changes, and the highlights are:* The main part is that new intrinsics, `__sanitizer_{start,finish}_fiber_switch` are now invoked around the stack-switching routines of fibers. This only works on Unix and is set to only compile when ASAN is enabled (otherwise everything is a noop). This required refactoring of things to get it all in just the right way for ASAN since it appears that these functions not only need to be called but more-or-less need to be adjacent to each other in the code. My guess is that while we're switching ASAN is in a "weird state" and it's not ready to run arbitrary code.* Stacks are a problem. The above issue in LLVM outlines how stacks cannot be deallocated at this time because if the deallocated virtual memory is later used for the heap then ASAN will have a false positive about stack overflow. To handle this stacks are specially handled in asan mode by using a special allocation path that never deallocates stacks. This logic additionally applies to the pooling allocator which uses a different stack allocation strategy with ASAN.With all of the above a new fuzzer is added. This fuzzer generates anarbitrary module, selects an arbitrary means of async (e.g.epochs/fuel), and then tries to execute the exports of the module withvarious values. In general the fuzzer is looking for crashes/panics asopposed to correct answers as there's no oracle here. This is alsointended to stress the code used to switch on and off stacks.* Fix non-async build* Remove unused import* Review comments* Fix compile on MIRI* Fix Windows build List of files: /wasmtime-44.0.1/fuzz/fuzz_targets/call_async.rs Tue, 23 Apr 2024 19:18:09 +0000 Alex Crichton <alex@alexcrichton.com>