gh-115832: Fix instrumentation version mismatch during interpreter shutdown (#115856)

A previous commit introduced a bug to `interpreter_clear()`: it set
`interp->ceval.instrumentation_version` to 0, without making the corresponding
change to `tstate->eval_breaker` (which holds a thread-local copy of the
version). After this happens, Python code can still run due to object finalizers
during a GC, and the version check in bytecodes.c will see a different result
than the one in instrumentation.c causing an infinite loop.

The fix itself is straightforward: clear `tstate->eval_breaker` when clearing
`interp->ceval.instrumentation_version`.

2 files changed, 41 insertions, 1 deletions

diff --git a/Lib/test/_test_monitoring_shutdown.py b/Lib/test/_test_monitoring_shutdown.py
new file mode 100644
index 0000000..3d0fbec
--- /dev/null
+++ b/Lib/test/_test_monitoring_shutdown.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+# gh-115832: An object destructor running during the final GC of interpreter
+# shutdown triggered an infinite loop in the instrumentation code.
+
+import sys
+
+class CallableCycle:
+    def __init__(self):
+        self._cycle = self
+
+    def __del__(self):
+        pass
+
+    def __call__(self, code, instruction_offset):
+        pass
+
+def tracefunc(frame, event, arg):
+    pass
+
+def main():
+    tool_id = sys.monitoring.PROFILER_ID
+    event_id = sys.monitoring.events.PY_START
+
+    sys.monitoring.use_tool_id(tool_id, "test profiler")
+    sys.monitoring.set_events(tool_id, event_id)
+    sys.monitoring.register_callback(tool_id, event_id, CallableCycle())
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/Lib/test/test_monitoring.py b/Lib/test/test_monitoring.py
index b027959..1e77eb6 100644
--- a/Lib/test/test_monitoring.py
+++ b/Lib/test/test_monitoring.py
@@ -9,7 +9,8 @@ import textwrap
 import types
 import unittest
 import asyncio
-from test.support import requires_specialization
+from test import support
+from test.support import requires_specialization, script_helper
 
 PAIR = (0,1)
 
@@ -1858,3 +1859,12 @@ class TestTier2Optimizer(CheckEvents):
             sys.monitoring.register_callback(TEST_TOOL, E.LINE, None)
             sys.monitoring.set_events(TEST_TOOL, 0)
         self.assertGreater(len(events), 250)
+
+class TestMonitoringAtShutdown(unittest.TestCase):
+
+    def test_monitoring_live_at_shutdown(self):
+        # gh-115832: An object destructor running during the final GC of
+        # interpreter shutdown triggered an infinite loop in the
+        # instrumentation code.
+        script = support.findfile("_test_monitoring_shutdown.py")
+        script_helper.run_test_script(script)