wasmtime / PR #8742 Add a fuzz target for exercising boun... · git-wasmtime

Mind adding a memory64 knob to this as well? Also mind adding some docs for what each field member is? For example at a glance I'm not sure what growth is.

Wasmtime GitHub notifications bot (Jun 04 2024 at 21:33):

alexcrichton created PR review comment:

Also could this grow a fully general WasmtimeConfig? It would be good to test various compilation settings, Winch, the pooling allocator, etc.

Wasmtime GitHub notifications bot (Jun 04 2024 at 21:33):

alexcrichton created PR review comment:

Does this mean that memories are going to grow an arbitrary 32-bit amount of bytes? If so should that be capped here to stay within limits on oss-fuzz?

Wasmtime GitHub notifications bot (Jun 04 2024 at 23:44):

github-actions[bot] commented on PR #8742:

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Wasmtime GitHub notifications bot (Jun 05 2024 at 13:02):

fitzgen commented on PR #8742:

Any particular motivation for this or just curious to see how it fares?

I started writing this for my implementation of the custom-page-sizes proposal, but figured I'd split it out and land it first to keep PRs small.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:05):

fitzgen submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:05):

fitzgen created PR review comment:

Ha, I originally had that and rewrote it into the text format to get a little bit better throughput for the fuzzer. I can add a comment giving an overview of the generated module or something to make readability a bit better at a glance though.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:05):

fitzgen edited PR review comment.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:05):

fitzgen submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:05):

fitzgen created PR review comment:

Good idea, will do.

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:07):

fitzgen created PR review comment:

An arbitrary 32-bit number of pages. I figured we could just allow and ignore growth failure, but will that run afoul of oss-fuzz?

Wasmtime GitHub notifications bot (Jun 05 2024 at 13:07):

fitzgen submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 14:27):

alexcrichton submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 14:27):

alexcrichton created PR review comment:

I think so yeah, but not always. Oss-fuzz/libfuzzer I think override malloc and mainly look at the heap size through that but IIRC it also occasionally looks through vm stats and looks for things like mmap, so we could allocate 1G here and blow the limits on oss-fuzz when it gets around to detecting that. Given that I think we'll only want growths which are guaranteed to either succeed for fail given our memory limits.

Wasmtime GitHub notifications bot (Jun 05 2024 at 17:48):

fitzgen requested cfallin for a review on PR #8742.

Wasmtime GitHub notifications bot (Jun 05 2024 at 17:48):

fitzgen updated PR #8742.

Wasmtime GitHub notifications bot (Jun 05 2024 at 17:48):

fitzgen requested wasmtime-compiler-reviewers for a review on PR #8742.

Wasmtime GitHub notifications bot (Jun 05 2024 at 19:12):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 19:12):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 19:12):

cfallin created PR review comment:

Should this be 1 rather than 8? Otherwise this iteration range is empty...

Wasmtime GitHub notifications bot (Jun 05 2024 at 21:18):

alexcrichton submitted PR review.

Wasmtime GitHub notifications bot (Jun 05 2024 at 21:18):

alexcrichton created PR review comment:

This can use input.config.to_store() which should also handle things like epochs/fuel configuration I believe.

Wasmtime GitHub notifications bot (Jun 06 2024 at 13:29):

fitzgen submitted PR review.

Wasmtime GitHub notifications bot (Jun 06 2024 at 13:29):

fitzgen created PR review comment:

Unfortunately, we can't use that since we are setting extra config settings based on the arbitrary heap image, but we don't have access to the config/engine if we use that method.

Wasmtime GitHub notifications bot (Jun 06 2024 at 13:38):

fitzgen updated PR #8742.

Wasmtime GitHub notifications bot (Jun 06 2024 at 13:38):

fitzgen has enabled auto merge for PR #8742.

Wasmtime GitHub notifications bot (Jun 06 2024 at 14:01):

fitzgen merged PR #8742.

Last updated: Dec 13 2025 at 19:03 UTC