Stop non-main threads during interpreter finalization (#7349)

youknowone · web-flow · commit 62766fd4a90a · 2026-03-05T10:21:44.000+09:00
Raise SystemExit in check_signals() for non-main threads
once the finalizing flag is set. Without GIL, this serves
as the checkpoint where daemon threads detect shutdown,
analogous to CPython's _PyThreadState_MustExit in take_gil.
diff --git a/crates/vm/src/vm/mod.rs b/crates/vm/src/vm/mod.rs
@@ -1479,6 +1479,13 @@ impl VirtualMachine {
     /// Checks for triggered signals and calls the appropriate handlers. A no-op on
     /// platforms where signals are not supported.
     pub fn check_signals(&self) -> PyResult<()> {
+        #[cfg(feature = "threading")]
+        if self.state.finalizing.load(Ordering::Acquire) && !self.is_main_thread() {
+            // once finalization starts,
+            // non-main Python threads should stop running bytecode.
+            return Err(self.new_exception(self.ctx.exceptions.system_exit.to_owned(), vec![]));
+        }
+
         #[cfg(not(target_arch = "wasm32"))]
         {
             crate::signal::check_signals(self)
