Clear exit if START_EXECUTOR detects that the executor is invalid

python · markshannon · Aug 1, 2025 · Jul 7, 2025 · Jul 7, 2025 · Jul 7, 2025
commit 989a882896e9798e453e2aff0d0464d2bbef2332
diff --git a/Include/internal/pycore_optimizer.h b/Include/internal/pycore_optimizer.h
@@ -363,6 +363,8 @@ static inline _PyExecutorObject *_PyExecutor_FromExit(_PyExitData *exit)
 
 extern _PyExecutorObject *_PyExecutor_GetColdExecutor(void);
 
+PyAPI_FUNC(void) _PyExecutor_ClearExit(_PyExitData *exit);
+
 static inline int is_terminator(const _PyUOpInstruction *uop)
 {
     int opcode = uop->opcode;

diff --git a/Include/internal/pycore_uop_metadata.h b/Include/internal/pycore_uop_metadata.h
@@ -2965,6 +2965,7 @@ dummy_func(
                     this_instr[1].counter = initial_jump_backoff_counter();
                     assert(tstate->current_executor == NULL);
                     assert(executor != tstate->interp->cold_executor);
+                    tstate->jit_exit = NULL;
                     GOTO_TIER_TWO(executor);
                 }
             }
@@ -3030,6 +3031,7 @@ dummy_func(
                 DISPATCH_GOTO();
             }
             assert(executor != tstate->interp->cold_executor);
+            tstate->jit_exit = NULL;
             GOTO_TIER_TWO(executor);
             #else
             Py_FatalError("ENTER_EXECUTOR is not supported in this build");
@@ -5352,6 +5354,12 @@ dummy_func(
             current_executor = (_PyExecutorObject*)executor;
 #endif
             tstate->current_executor = (PyObject *)executor;
+            if (!current_executor->vm_data.valid) {
+                assert(tstate->jit_exit->executor == current_executor);
+                assert(tstate->current_executor == current_executor);
+                _PyExecutor_ClearExit(tstate->jit_exit);
+                DEOPT_IF(true);
+            }
         }
 
         tier2 op(_MAKE_WARM, (--)) {

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
@@ -584,7 +584,6 @@ translate_bytecode_to_trace(
             code->co_firstlineno,
             2 * INSTR_IP(initial_instr, code));
     ADD_TO_TRACE(_START_EXECUTOR, 0, (uintptr_t)instr, INSTR_IP(instr, code));
-    ADD_TO_TRACE(_CHECK_VALIDITY, 0, 0, 0);
     ADD_TO_TRACE(_MAKE_WARM, 0, 0, 0);
     uint32_t target = 0;
 
@@ -1494,6 +1493,16 @@ _PyExecutor_GetColdExecutor(void)
     return cold;
 }
 
+void
+_PyExecutor_ClearExit(_PyExitData *exit)
+{
+    if (exit == NULL) {
+        return;
+    }
+    _PyExecutorObject *old = exit->executor;
+    exit->executor = _PyExecutor_GetColdExecutor();
+    Py_DECREF(old);
+}
 
 /* Detaches the executor from the code object (if any) that
  * holds a reference to it */