This input when run with this host:
use std::pin::Pin;
use std::task::{Context, Poll};
use wasmtime::*;
#[tokio::main]
async fn main() -> wasmtime::Result<()> {
let mut config = Config::new();
config.consume_fuel(true);
config.wasm_gc(true);
config.wasm_exceptions(true);
config.wasm_function_references(true);
let engine = Engine::new(&config)?;
let mut store = Store::new(&engine, ());
store.fuel_async_yield_interval(Some(85460))?;
store.set_fuel(u64::MAX)?;
let module = Module::from_file(&engine, "./hi.wat")?;
let mut linker = Linker::new(&engine);
linker.define_unknown_imports_as_default_values(&mut store, &module)?;
let instance = linker.instantiate_async(&mut store, &module).await?;
let f = instance.get_func(&mut store, "").unwrap();
let mut rets = [Val::I32(0); 4];
for _ in 0..2 {
let _ = Timeout {
future: f.call_async(&mut store, &[], &mut rets),
polls: 5684,
}
.await;
}
Ok(())
}
struct Timeout<F> {
future: F,
polls: u32,
}
#[derive(Debug)]
enum Exhausted {
Polls,
}
impl<F: Future> Future for Timeout<F> {
type Output = Result<F::Output, Exhausted>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let (polls, future) = unsafe {
let me = self.get_unchecked_mut();
(&mut me.polls, Pin::new_unchecked(&mut me.future))
};
match future.poll(cx) {
Poll::Ready(val) => Poll::Ready(Ok(val)),
Poll::Pending => {
if *polls == 0 {
log::warn!("future operation ran out of polls");
return Poll::Ready(Err(Exhausted::Polls));
}
*polls -= 1;
Poll::Pending
}
}
}
}will panic:
$ RUSTFLAGS=--cfg=gc_zeal cargo run --bin repro
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.11s
Running `target/debug/repro`
thread 'main' (855450) panicked at crates/wasmtime/src/runtime/vm/gc/enabled/copying.rs:863:13:
newly allocated GC object at index 32784 is not fully poisoned; freed memory was corrupted
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Bisection shows #13491 as the culprit, cc @fitzgen
This input when run with this host:
will panic:
Bisection shows #13491 as the culprit, cc @fitzgen