From: Mikhail Efimov <efimov.mikhail@gmail.com>
Date: Wed, 12 Nov 2025 19:04:02 +0000 (+0300)
Subject: gh-140936: Fix JIT assertion crash at finalization if some generator is alive (GH... 
X-Git-Tag: v3.15.0a2~69
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=35ed3e4cedc8aef3936da81a6b64e90374532b13;p=thirdparty%2FPython%2Fcpython.git

gh-140936: Fix JIT assertion crash at finalization if some generator is alive (GH-140969)
---

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 4e94f62d35eb..e65556fb28f9 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -2660,6 +2660,25 @@ class TestUopsOptimization(unittest.TestCase):
 
         f()
 
+    def test_interpreter_finalization_with_generator_alive(self):
+        script_helper.assert_python_ok("-c", textwrap.dedent("""
+            import sys
+            t = tuple(range(%d))
+            def simple_for():
+                for x in t:
+                    x
+
+            def gen():
+                try:
+                    yield
+                except:
+                    simple_for()
+
+            sys.settrace(lambda *args: None)
+            simple_for()
+            g = gen()
+            next(g)
+        """ % _testinternalcapi.SPECIALIZATION_THRESHOLD))
 
 
 def global_identity(x):
diff --git a/Python/optimizer.c b/Python/optimizer.c
index f44f8a9614b8..3b7e2dafab85 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -118,7 +118,13 @@ _PyOptimizer_Optimize(
 {
     _PyStackRef *stack_pointer = frame->stackpointer;
     PyInterpreterState *interp = _PyInterpreterState_GET();
-    assert(interp->jit);
+    if (!interp->jit) {
+        // gh-140936: It is possible that interp->jit will become false during
+        // interpreter finalization. However, the specialized JUMP_BACKWARD_JIT
+        // instruction may still be present. In this case, we should
+        // return immediately without optimization.
+        return 0;
+    }
     assert(!interp->compiling);
 #ifndef Py_GIL_DISABLED
     interp->compiling = true;