Stream: git-wasmtime

Topic: wasmtime / issue #8446 Winch runtime segmentation fault i...

Wasmtime GitHub notifications bot (Apr 23 2024 at 16:42):

TerrorJack opened issue #8446:

Reproducer: https://files.catbox.moe/jbsi1b.wasm

When wasmtime-cli-v20.0.0 is built with winch on x86_64-linux and the above file is run with wasmtime run -C compiler=winch --env PWD=/ --dir "$PWD"::/ -W tail-call -- hello.wasm, then it fails with a segmentation fault. Remove -C compiler=winch and it properly runs without any issue. The module above does not contain any opcodes unsupported by winch at this time.

Wasmtime GitHub notifications bot (Apr 23 2024 at 16:46):

saulecabrera added the winch label to Issue #8446.

Wasmtime GitHub notifications bot (Apr 23 2024 at 16:46):

saulecabrera added the bug label to Issue #8446.

Wasmtime GitHub notifications bot (Apr 23 2024 at 17:15):

saulecabrera commented on issue #8446:

Thanks for the report!

A couple of questions that might help diagnose the root cause:

• The Wasm binary is ~25MB in size, have you tried reducing the failure with wasm-tools shrink as outlined here https://github.com/bytecodealliance/wasmtime/blob/main/docs/contributing-reducing-test-cases.md?
• Does the Wasm program need access to the current working directory? (e.g. the command in the report is making use of --dir) If so, could you speak a bit more about what are the expectations between the program and that directory? This might make it easier to reduce the program and reproduce the bug in isolation. FWIW, I tried on a Linux machine, without the --env and without the --dir arguments and I get the following result:

main = putStrLn "hello world"

Wasmtime GitHub notifications bot (Apr 23 2024 at 17:41):

saulecabrera commented on issue #8446:

I was able to reproduce, only when the --env, --dir and -W tail-call params are specified (i.e. when -W tail-call is dropped, it doesn't segfault), which makes me think that it has to do with the tail call calling convention and its support in Winch.

Wasmtime GitHub notifications bot (Apr 23 2024 at 19:14):

saulecabrera commented on issue #8446:

FYI, I've opened https://github.com/bytecodealliance/wasmtime/pull/8447, to address this issue.

Wasmtime GitHub notifications bot (Apr 23 2024 at 21:14):

alexcrichton closed issue #8446:

Reproducer: https://files.catbox.moe/jbsi1b.wasm

When wasmtime-cli-v20.0.0 is built with winch on x86_64-linux and the above file is run with wasmtime run -C compiler=winch --env PWD=/ --dir "$PWD"::/ -W tail-call -- hello.wasm, then it fails with a segmentation fault. Remove -C compiler=winch and it properly runs without any issue. The module above does not contain any opcodes unsupported by winch at this time.

Last updated: Dec 13 2025 at 19:03 UTC