Repository: rust
Issue: wasi threads mpsc channel hang on sched_yield only on debug rust build
Labels: C-bug,T-libs,O-wasi

There is an issue with rust wasi threads where using mpsc channel can hang / deadlock only when compiled in debug mode

With this code, with `wasm32-wasi-preview1-threads` target:
```
use std::sync::mpsc;
use std::thread;

fn main() {
    let (send, recv) = mpsc::channel();
    let thread = thread::spawn(move || {
        let v = vec![1, 2, 3];
        println!("\tsending {:?}", v);
        send.send(v).unwrap();
        println!("\tsent");
    });


    println!("receiving");
    
    let v= recv.recv().unwrap();

    println!("received {:?}", v);

    thread.join().unwrap();
}
```

I've created this repository, which provides an easy way of reproducing the bug:

https://github.com/cimacmillan/WasiThreadsSchedYieldBug

I expected to see this happen: 
```
receiving
        sending [1, 2, 3]
        sent
received [1, 2, 3]
```

Instead, this happened: 
```
receiving
        sending [1, 2, 3]
```

I've reproduced this on wasmtime and wamr.

### Notes

If vec is placed in a box, it succeeds on both debug and release 
```
let v = Box::new(vec![1, 2, 3]);
println!("\tsending {:?}", v);
send.send(v).unwrap();
```

Using a stack allocated array, it succeeds on release but crashes on debug 
```
thread 'main' panicked at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/mod.rs:1439:40:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Error: failed to run main module `target/wasm32-wasi-preview1-threads/debug/wasi_channel.wasm`

Caused by:
    0: failed to invoke command default
    1: error while executing at wasm backtrace:
           0: 0x27b6d - panic_abort::__rust_start_panic::abort::hbcfb3c5651cde4fc
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/panic_abort/src/lib.rs:84:17              - __rust_start_panic
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/panic_abort/src/lib.rs:38:5
           1: 0x27622 - rust_panic
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:757:25
           2: 0x275a9 - std::panicking::rust_panic_with_hook::h6c1623ae744881b6
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:729:5
           3: 0x26536 - std::panicking::begin_panic_handler::{{closure}}::h8474ba3fc2a2f64f
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:597:13
           4: 0x2649b - std::sys_common::backtrace::__rust_end_short_backtrace::h2d8a3004b92235a1
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:170:18
           5: 0x26efc - rust_begin_unwind
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:595:5
           6: 0x2d42e - core::panicking::panic_fmt::h4d6ec91b4ec3c102
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:67:14
           7: 0x2d9b9 - core::panicking::panic::h034632322060c32c
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:117:5
           8: 0x17e9c - core::option::Option<T>::unwrap::h1863121d2cc0b0ed
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/option.rs:935:21              - std::thread::JoinInner<T>::join::hd31db5945ffb3f2c
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/mod.rs:1439:40
           9: 0x18045 - std::thread::JoinHandle<T>::join::h4dbbb2a53ac5f6d8
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/mod.rs:1571:9
          10: 0x24cb - wasi_channel::main::h820cc1b51aa05b11
                           at /home/ANT.AMAZON.COM/cmmacmil/Workplace/WasiThreadsSchedYieldBug/src/main.rs:20:5
          11: 0x13576 - core::ops::function::FnOnce::call_once::hb0a25fce8d6fee0e
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ops/function.rs:250:5
          12: 0xbd86 - std::sys_common::backtrace::__rust_begin_short_backtrace::hcb7642304aef178a
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:154:18
          13: 0xfca9 - std::rt::lang_start::{{closure}}::hff3d73af1b02f1d1
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:166:18
          14: 0x2331a - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h419298144f8c584c
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ops/function.rs:284:13              - std::panicking::try::do_call::h5a71f345767668ef
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:502:40              - std::panicking::try::h5a7441a0b5ca82dd
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:466:19              - std::panic::catch_unwind::h4144d543aad3e5b6
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panic.rs:142:14              - std::rt::lang_start_internal::{{closure}}::h8e9bcf681666a716
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:148:48              - std::panicking::try::do_call::h61bb14bafca96d71
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:502:40              - std::panicking::try::h011f4feb1eca4f94
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:466:19              - std::panic::catch_unwind::hf0cc29067d9aa254
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panic.rs:142:14              - std::rt::lang_start_internal::hee10ca7e79926ed8
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:148:20
          15: 0xfc46 - std::rt::lang_start::h261b20e17f46f2bb
                           at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:165:17
          16: 0x253c - <unknown>!__main_void
          17:  0x719 - <unknown>!_start
    2: wasm trap: wasm `unreachable` instruction executed
```

Tracing using wasm-micro-runtime wasm debugger shows both threads paused on exception 
Main thread
```
std::sys::wasi::alloc::_$LT$impl$u20$core..alloc..global..GlobalAlloc$u20$for$u20$std..alloc..System$GT$::alloc::haa63c39ee08f2074 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/alloc.rs:14)
__rdl_alloc (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/alloc.rs:380)
 (:0)
alloc::alloc::alloc::h42374113b40c16ed (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:98)
alloc::alloc::Global::alloc_impl::h9090710806748dc2 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:181)
_$LT$alloc..alloc..Global$u20$as$u20$core..alloc..Allocator$GT$::allocate::h71d2a35315712f79 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:241)
alloc::raw_vec::finish_grow::ha5efa382d4be5115 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/raw_vec.rs:485)
alloc::raw_vec::RawVec$LT$T$C$A$GT$::grow_amortized::hf692d68114f3755b (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/raw_vec.rs:404)
alloc::raw_vec::RawVec$LT$T$C$A$GT$::reserve_for_push::h2a968592231ee383 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/raw_vec.rs:302)
alloc::vec::Vec$LT$T$C$A$GT$::push::ha56c219806196dc1 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/vec/mod.rs:1829)
std::sync::mpmc::waker::Waker::register_with_packet::h415bb41d0e6ccf14 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/waker.rs:50)
std::sync::mpmc::waker::Waker::register::hece34a0b16653117 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/waker.rs:44)
std::sync::mpmc::waker::SyncWaker::register::h7c5d2119ed1febeb (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/waker.rs:155)
std::sync::mpmc::list::Channel$LT$T$GT$::recv::_$u7b$$u7b$closure$u7d$$u7d$::hdc64ce948da1d89a (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/list.rs:436)
std::sync::mpmc::context::Context::with::_$u7b$$u7b$closure$u7d$$u7d$::ha81a21b45c2235c8 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/context.rs:50)
std::sync::mpmc::context::Context::with::_$u7b$$u7b$closure$u7d$$u7d$::he57ca4f13f038b26 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/context.rs:58)
std::thread::local::LocalKey$LT$T$GT$::try_with::h54045f9a24ff4e0f (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:270)
std::sync::mpmc::context::Context::with::h9f6c91eccd7e1618 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/context.rs:53)
```

Spawned thread
```
std::sys::wasi::alloc::_$LT$impl$u20$core..alloc..global..GlobalAlloc$u20$for$u20$std..alloc..System$GT$::alloc::haa63c39ee08f2074 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/alloc.rs:14)
__rdl_alloc (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/alloc.rs:380)
 (:0)
alloc::alloc::alloc::h42374113b40c16ed (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:98)
alloc::alloc::Global::alloc_impl::h9090710806748dc2 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:181)
_$LT$alloc..alloc..Global$u20$as$u20$core..alloc..Allocator$GT$::allocate::h71d2a35315712f79 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:241)
alloc::alloc::exchange_malloc::h4e69b088f2a2057f (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/alloc.rs:330)
alloc::boxed::Box$LT$T$GT$::new::h12d236dc4a77b137 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/boxed.rs:217)
std::sync::mpmc::list::Channel$LT$T$GT$::start_send::h8f9ef938a1752225 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/list.rs:209)
std::sync::mpmc::list::Channel$LT$T$GT$::send::hd1588ed8e20b059b (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/list.rs:402)
std::sync::mpmc::Sender$LT$T$GT$::send::hdc2374ba0d3a3e44 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpmc/mod.rs:128)
std::sync::mpsc::Sender$LT$T$GT$::send::h4cdca901b00daa1f (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mpsc/mod.rs:613)
wasm_hello_world::main::_$u7b$$u7b$closure$u7d$$u7d$::hce684d33494d1d0c (/home/ANT.AMAZON.COM/cmmacmil/Workplace/rustc/test/wasm_hello_world/src/main.rs:9)
std::sys_common::backtrace::__rust_begin_short_backtrace::h22749124b985e533 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/backtrace.rs:154)
std::thread::Builder::spawn_unchecked_::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h25bdfa1e0f7ce137 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/mod.rs:529)
_$LT$core..panic..unwind_safe..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h9940955c78c8f231 (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/panic/unwind_safe.rs:271)
std::panicking::try::do_call::h032c93401696362e (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:502)
std::panicking::try::h20a3486b63cbd1af (/home/ANT.AMAZON.COM/cmmacmil/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:466)
```

### Meta
`rustc --version --verbose`:
```
rustc 1.73.0 (cc66ad468 2023-10-03)
binary: rustc
commit-hash: cc66ad468955717ab92600c770da8c1601a4ff33
commit-date: 2023-10-03
host: x86_64-unknown-linux-gnu
release: 1.73.0
LLVM version: 17.0.2
```