gh-141786: Fix missing parent executor during JIT trace

Lib/test/test_capi/test_opt.py

@@ -2695,6 +2695,144 @@ def recursive_wrapper_4569():
                     pass
         """))
 
+    def test_executor_invalidation_does_not_crash(self):
+        script_helper.assert_python_ok("-c", textwrap.dedent("""
+        import random
+
+        rand = random.Random(38720)
+        import sys
+
+        def b():
+            for c in range(23):
+                rand.random()
+            rand.random()
+            if rand.random() > 0.1:
+                rand.random()
+            rand.random()
+            rand.random()
+            for c in range(4):
+                rand.random()
+            if rand.random():
+                0
+            if rand.random() > 0.1:
+                rand.random()
+            rand.random()
+            if rand.random():
+                rand.random()
+            if rand.random():
+                rand.random()
+            rand.random()
+            if rand.random():
+                rand.random()
+            rand.random()
+            if rand.random():
+                if rand.random() > 0.1:
+                    rand.random()
+            if rand.random() < rand.random():
+                ...
+            if rand.random() < rand.random():
+                ...
+            if rand.random():
+                ...
+            if rand.random() > 0.1:
+                rand.random()
+            rand.random()
+            for c in range(12):
+                rand.random()
+
+            def random(B):
+                if rand.random() < 0.1:
+                    random(B)
+
+            def Random(B):
+                if rand.random():
+                    random(B)
+
+            def b(B):
+                if rand.random():
+                    Random(B)
+
+            def c(B):
+                if rand.random() < 0.1:
+                    b(B)
+
+            def a(B):
+                if rand.random() > 0.1:
+                    c(B)
+
+            def A(B):
+                if rand.random() > 0.1:
+                    a(B)
+
+            def C(B):
+                if rand.random() > 0.1:
+                    A(B)
+
+            def B(B):
+                if rand.random() < 0.1:
+                    C(B)
+
+            for D in range(200):
+                try:
+                    B(D)
+                except:
+                    ...
+
+            class A:
+                def __del__(C):
+                    b = sys._getframe(1)
+                    exec("D=0", b.f_globals, b.f_locals)
+
+            B = A()
+            if rand.random() < 0.1:
+                if rand.random() < 0.1:
+                    if rand.random() < 0.1:
+                        for D in range(D):
+                            if rand.random() < 0.1:
+                                if rand.random() > 0.1:
+                                    if rand.random():
+                                        if rand.random() > rand.random():
+                                            C
+                            if rand.random() < 0.1:
+                                if rand.random() < 0.1:
+                                    if rand.random() < 0.1:
+                                        del B
+                            if rand.random() < 0.1:
+                                if rand.random() < 0.1:
+                                    if rand.random():
+                                        0
+            if rand.random() > 0.1:
+                if rand.random() > 0.1:
+                    rand.random()
+            rand.random()
+            if rand.random() > 0.1:
+                rand.random()
+            rand.random()
+            if rand.random() > 0.1:
+                if rand.random() > 0.1:
+                    rand.random()
+            rand.random()
+            rand.random()
+            rand.random()
+            if rand.random() > 0.1:
+                if rand.random() > 0.1:
+                    rand.random()
+                    if rand.random() > rand.random():
+                        0
+            if rand.random():
+                C
+            if rand.random() > 0.1:
+                rand.random()
+            rand.random()
+            for c in range(3):
+                if rand.random():
+                    0
+            for c in range(2):
+                rand.random()
+
+        for D in range(5064):
+            b()
+        """))
 
 def global_identity(x):
     return x

Python/ceval.c

@@ -1408,7 +1408,9 @@ stop_tracing_and_jit(PyThreadState *tstate, _PyInterpreterFrame *frame)
         // Likewise, we hold a strong reference to the executor containing this exit, so the exit is guaranteed
         // to be valid to access.
         if (err <= 0) {
-            exit->temperature = restart_backoff_counter(exit->temperature);
+            if (exit->executor->vm_data.linked && exit->executor->vm_data.valid) {
+                exit->temperature = restart_backoff_counter(exit->temperature);
+            }
         }
         else {
             exit->temperature = initial_temperature_backoff_counter();

Python/optimizer.c

@@ -140,6 +140,14 @@ _PyOptimizer_Optimize(
     }
     assert(!interp->compiling);
     assert(_tstate->jit_tracer_state.initial_state.stack_depth >= 0);
+    _PyExitData *exit = _tstate->jit_tracer_state.initial_state.exit;
+    _PyExecutorObject *cold_executor = _PyExecutor_GetColdExecutor();
+    if (exit != NULL &&
+        (!exit->executor->vm_data.linked || !exit->executor->vm_data.valid) &&
+        exit->executor != cold_executor) {
+        // gh-141786 Parent executor is either unlinked or invalid - cannot optimize.
+        return 0;
+    }
 #ifndef Py_GIL_DISABLED
     assert(_tstate->jit_tracer_state.initial_state.func != NULL);
     interp->compiling = true;
@@ -185,7 +193,6 @@ _PyOptimizer_Optimize(
     else {
         executor->vm_data.code = NULL;
     }
-    _PyExitData *exit = _tstate->jit_tracer_state.initial_state.exit;
     if (exit != NULL) {
         exit->executor = executor;
     }