Update definition of wasmtime_func_call_unchecked.
#245
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I can consistently reproduce the panic using the following C# console program on Windows 10 Version 21H2 x64 (using .NET 7.0.5), even without attaching a debugger (and I assume, but haven't tested, that it would also occur on Linux, as it also occured there on CI): using Wasmtime;
using var engine = new Engine();
using var module = Module.FromText(engine, "Error", @"
(module
(import """" ""host_start"" (func $host_start))
(import """" ""host_get_trap"" (func $host_get_trap))
(export ""host_get_trap"" (func $host_get_trap))
(start $start)
(func $start
(call $host_start)
)
)
");
using var store = new Store(engine);
using var linker = new Linker(engine);
linker.Define("", "host_start", Function.FromCallback(
store,
(caller, args, results) => { },
Array.Empty<ValueKind>(),
Array.Empty<ValueKind>()));
linker.Define("", "host_get_trap", Function.FromCallback(
store,
(caller, args, results) => throw new Exception("This is an expected exception."),
Array.Empty<ValueKind>(),
Array.Empty<ValueKind>()));
var instance = linker.Instantiate(store, module);
var getTrap = instance.GetFunction("host_get_trap")!;
// This stackalloc seems necessary to trigger the trap at least
// when using wasmtime_func_call_unchecked.
Span<byte> testStack = stackalloc byte[8192];
try
{
getTrap.Invoke();
}
catch (WasmtimeException ex)
{
Console.WriteLine(ex.ToString());
}Note that this uses When using Bisecting shows that this issue appears to have been introduced with commit bytecodealliance/wasmtime@913efdf (bytecodealliance/wasmtime#6262); when using the previous commit bytecodealliance/wasmtime@5b9121f, the output is as expected: |
|
I'll see if I can make a pure |
|
I've managed to reproduce with this: #[test]
fn regression() -> Result<()> {
let engine = Engine::default();
let module = Module::new(
&engine,
r#"
(module
(import "" "host_start" (func $host_start))
(import "" "host_get_trap" (func $host_get_trap))
(export "get_trap" (func $host_get_trap))
(start $start)
(func $start
(call $host_start)
)
)
"#,
)?;
let mut store = Store::new(&engine, ());
let mut linker = Linker::new(&engine);
let host_start = Func::new(
&mut store,
FuncType::new([], []),
|_caller, _args, _results| Ok(()),
);
linker.define(&store, "", "host_start", host_start)?;
let host_get_trap = Func::new(
&mut store,
FuncType::new([], []),
|_caller, _args, _results| Err(anyhow::anyhow!("trap!!!")),
);
linker.define(&store, "", "host_get_trap", host_get_trap)?;
let instance = linker.instantiate(&mut store, &module)?;
let get_trap = instance.get_func(&mut store, "get_trap").unwrap();
let err = get_trap.call(&mut store, &[], &mut []).unwrap_err();
assert!(err.to_string().contains("trap!!!"));
Ok(())
}Thanks for filing an issue and providing a test case! |
fitzgen
added a commit
to fitzgen/wasmtime
that referenced
this pull request
May 1, 2023
… Wasm Fixes a regression from bytecodealliance#6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: [email protected]
fitzgen
added a commit
to fitzgen/wasmtime
that referenced
this pull request
May 1, 2023
… Wasm Fixes a regression from bytecodealliance#6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: Alex Crichton <[email protected]>
fitzgen
added a commit
to fitzgen/wasmtime
that referenced
this pull request
May 2, 2023
… Wasm Fixes a regression from bytecodealliance#6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: Alex Crichton <[email protected]>
github-merge-queue bot
pushed a commit
to bytecodealliance/wasmtime
that referenced
this pull request
May 2, 2023
… Wasm (#6321) Fixes a regression from #6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-authored-by: Alex Crichton <[email protected]>
fitzgen
added a commit
to fitzgen/wasmtime
that referenced
this pull request
May 2, 2023
… Wasm Fixes a regression from bytecodealliance#6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: Alex Crichton <[email protected]>
github-merge-queue bot
pushed a commit
to bytecodealliance/wasmtime
that referenced
this pull request
May 3, 2023
…ng Wasm (#6321) * wasmtime: Fix resetting stack-walking registers when entering/exiting Wasm Fixes a regression from #6262, originally reported in bytecodealliance/wasmtime-dotnet#245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: Alex Crichton <[email protected]> * Plumb through `VMRuntimeLimits` when capturing stack traces This way we can differentiate between the same module loaded in different stores and avoid leaking other stores' frames into our backtraces. Co-Authored-By: Jamey Sharp <[email protected]> --------- Co-authored-by: Alex Crichton <[email protected]> Co-authored-by: Jamey Sharp <[email protected]>
|
Thanks for fixing the issue @fitzgen! The unit tests now run successfully (also on my machine). |
peterhuene
approved these changes
May 3, 2023
|
@kpreisser thanks for fixing this on the .NET SDK side! |
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Update definition of
wasmtime_func_call_unchecked. See bytecodealliance/wasmtime#6262Fixes #244
Note: The unit tests run successfully on my machine (Windows 10 x64) e.g. with
dotnet testor when running them in Visual Studio without debugging; but when I run them in Visual Studio with debugging, the testWasmtime.Tests.ErrorTests.ItPassesCallbackErrorCauseAsInnerExceptionalways fails with aSEHException, which seems to be caused by a Rust panic (using Wasmtime from commit b453c70d7af6db1550fd7bc17e2e69c88e89323b):I'm not sure what could be causing this, and why it happens only when running the tests with debugging.