gh-145376: Fix refleaks and double decref for code in Python/ (#145666)

Author: eendebakpt

Python/ceval.c

@@ -2243,6 +2243,7 @@ _PyEval_ExceptionGroupMatch(_PyInterpreterFrame *frame, PyObject* exc_value,
             if (f != NULL) {
                 PyObject *tb = _PyTraceBack_FromFrame(NULL, f);
                 if (tb == NULL) {
+                    Py_DECREF(wrapped);
                     return -1;
                 }
                 PyException_SetTraceback(wrapped, tb);

Python/crossinterp.c

@@ -1103,12 +1103,12 @@ _convert_exc_to_TracebackException(PyObject *exc, PyObject **p_tbexc)
     }
 
     PyObject *tbexc = PyObject_Call(create, args, kwargs);
-    Py_DECREF(args);
-    Py_DECREF(kwargs);
-    Py_DECREF(create);
     if (tbexc == NULL) {
         goto error;
     }
+    Py_DECREF(args);
+    Py_DECREF(kwargs);
+    Py_DECREF(create);
 
     *p_tbexc = tbexc;
     return 0;
@@ -1497,7 +1497,7 @@ _PyXI_excinfo_Apply(_PyXI_excinfo *info, PyObject *exctype)
 
     PyObject *formatted = _PyXI_excinfo_format(info);
     PyErr_SetObject(exctype, formatted);
-    Py_DECREF(formatted);
+    Py_XDECREF(formatted);
 
     if (tbexc != NULL) {
         PyObject *exc = PyErr_GetRaisedException();

Python/sysmodule.c

@@ -2499,7 +2499,7 @@ sys_remote_exec_impl(PyObject *module, int pid, PyObject *script)
     }
 
     if (PySys_Audit("sys.remote_exec", "iO", pid, script) < 0) {
-        return NULL;
+        goto error;
     }
 
     debugger_script_path = PyBytes_AS_STRING(path);