Jan 24, 2026 · Jan 20, 2026 · Jan 21, 2026
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
        """), PYTHON_JIT="1", PYTHON_JIT_STRESS="1")
        self.assertEqual(result[0].rc, 0, result)

    def test_144068_daemon_thread_jit_cleanup(self):
        result = script_helper.run_python_until_end('-c', textwrap.dedent("""
        import threading
        import time

        def hot_loop():
            end = time.time() + 5.0
            while time.time() < end:
                pass

        # Create a daemon thread that will be abandoned at shutdown
        t = threading.Thread(target=hot_loop, daemon=True)
        t.start()

        time.sleep(0.1)
        """), PYTHON_JIT="1", ASAN_OPTIONS="detect_leaks=1")
        self.assertEqual(result[0].rc, 0, result)
        stderr = result[0].err.decode('utf-8', errors='replace')
        self.assertNotIn('LeakSanitizer', stderr,
                         f"Memory leak detected by ASan:\n{stderr}")
        self.assertNotIn('_PyJit_TryInitializeTracing', stderr,
                         f"JIT tracer memory leak detected:\n{stderr}")

 def global_identity(x):
    return x

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-01-21-02-30-06.gh-issue-144068.9TTu7v.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-01-21-02-30-06.gh-issue-144068.9TTu7v.rst
 Fix JIT tracer memory leak, ensure the JIT tracer state is freed when daemon threads are cleaned up during interpreter shutdown.
diff --git a/Python/pystate.c b/Python/pystate.c

    _PyThreadState_ClearMimallocHeaps(tstate);

 #ifdef _Py_TIER2
    _PyJit_TracerFree((_PyThreadStateImpl *)tstate);
 #endif

    tstate->_status.cleared = 1;

    // XXX Call _PyThreadStateSwap(runtime, NULL) here if "current".
Original file line number	Diff line number	Diff line change
Expand Up		@@ -3792,6 +3792,29 @@ def __next__(self):
		"""), PYTHON_JIT="1", PYTHON_JIT_STRESS="1")
		self.assertEqual(result[0].rc, 0, result)

		def test_144068_daemon_thread_jit_cleanup(self):
		result = script_helper.run_python_until_end('-c', textwrap.dedent("""
		import threading
		import time

		def hot_loop():
		end = time.time() + 5.0
		while time.time() < end:
		pass

		# Create a daemon thread that will be abandoned at shutdown
		t = threading.Thread(target=hot_loop, daemon=True)
		t.start()

		time.sleep(0.1)
		"""), PYTHON_JIT="1", ASAN_OPTIONS="detect_leaks=1")
		self.assertEqual(result[0].rc, 0, result)
		stderr = result[0].err.decode('utf-8', errors='replace')
		self.assertNotIn('LeakSanitizer', stderr,
		f"Memory leak detected by ASan:\n{stderr}")
		self.assertNotIn('_PyJit_TryInitializeTracing', stderr,
		f"JIT tracer memory leak detected:\n{stderr}")

		def global_identity(x):
		return x

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Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fix JIT tracer memory leak, ensure the JIT tracer state is freed when daemon threads are cleaned up during interpreter shutdown.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1836,6 +1836,10 @@ PyThreadState_Clear(PyThreadState *tstate)

		_PyThreadState_ClearMimallocHeaps(tstate);

		#ifdef _Py_TIER2
		_PyJit_TracerFree((_PyThreadStateImpl *)tstate);
		#endif

		tstate->_status.cleared = 1;

		// XXX Call _PyThreadStateSwap(runtime, NULL) here if "current".
Expand Down