bpo-44525: Add recursive checks for `CALL_FUNCTION_BUILTIN_O` (GH-29271)

diff --git a/Python/ceval.c b/Python/ceval.c
index 4ac0b53dd6e466abd16bda76d7cd7b292df68d4d..d52ca9c65db22280fccf2e684e69062a8d77cbee 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4742,8 +4742,14 @@ check_eval_breaker:
             STAT_INC(CALL_FUNCTION, hit);
 
             PyCFunction cfunc = PyCFunction_GET_FUNCTION(callable);
+            // This is slower but CPython promises to check all non-vectorcall
+            // function calls.
+            if (_Py_EnterRecursiveCall(tstate, " while calling a Python object")) {
+                goto error;
+            }
             PyObject *arg = POP();
             PyObject *res = cfunc(PyCFunction_GET_SELF(callable), arg);
+            _Py_LeaveRecursiveCall(tstate);
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
 
             /* Clear the stack of the function object. */