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Merged
youknowone merged 2 commits into from
Oct 29, 2026
Merged

Avoid deadlocks during Windows overlapped cleanup #9452

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7694d66
Avoid deadlocks during Windows overlapped cleanup
1ndahous3 Oct 29, 2026
d3b25a9
Run asyncio shutdown regression on all platforms
1ndahous3 Oct 29, 2026
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43 changes: 25 additions & 18 deletions crates/stdlib/src/overlapped.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1134,32 +1134,39 @@ mod _overlapped {
let olderr = host_winapi::get_last_error();

// Cancel pending I/O and wait for completion
if !host_overlapped::has_overlapped_io_completed(&inner.overlapped)
let pending_error = if !host_overlapped::has_overlapped_io_completed(&inner.overlapped)
&& !matches!(inner.data, OverlappedData::NotStarted)
{
match host_overlapped::cancel_overlapped_for_drop(inner.handle, &inner.overlapped)
.error
{
ERROR_SUCCESS | ERROR_NOT_FOUND | ERROR_OPERATION_ABORTED => {}
_ => {
let msg = format!(
"{zelf:?} still has pending operation at deallocation, the process may crash"
);
let exc = vm.new_runtime_error(msg);
let err_msg = Some(format!(
"Exception ignored while deallocating overlapped operation {zelf:?}"
));
let obj: PyObjectRef = zelf.to_owned().into();
vm.run_unraisable(exc, err_msg, obj);
}
}
}
!matches!(
vm.allow_threads(|| host_overlapped::cancel_overlapped_for_drop(
inner.handle,
&inner.overlapped
))
.error,
ERROR_SUCCESS | ERROR_NOT_FOUND | ERROR_OPERATION_ABORTED
)
} else {
false
};

// Close the event handle
if !inner.overlapped.hEvent.is_null() {
let _ = host_winapi::close_handle(inner.overlapped.hEvent);
inner.overlapped.hEvent = core::ptr::null_mut();
}
// Debug formatting takes inner again; the unraisable hook can also
// re-enter this object. Complete native cleanup before either runs.
drop(inner);
if pending_error {
let msg = format!(
"{zelf:?} still has pending operation at deallocation, the process may crash"
);
let exc = vm.new_runtime_error(msg);
let err_msg = Some(format!(
"Exception ignored while deallocating overlapped operation {zelf:?}"
));
vm.run_unraisable(exc, err_msg, vm.ctx.none());
}

// Restore last error
host_windows::set_last_error(olderr);
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13 changes: 13 additions & 0 deletions extra_tests/snippets/stdlib_asyncio.py
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Original file line number Diff line number Diff line change
Expand Up @@ -5,10 +5,23 @@
these only run where they are reachable.
"""

import subprocess
import sys

from testutils import assert_raises

# An unclosed event loop must not deadlock during interpreter shutdown.
subprocess.run(
[
sys.executable,
"-c",
"import asyncio; loop = asyncio.new_event_loop(); "
"asyncio.set_event_loop(loop); loop.run_until_complete(asyncio.sleep(0))",
],
check=True,
timeout=10,
)

if sys.implementation.name != "rustpython":
sys.exit(0)

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