gh-120754: Fix memory leak in FileIO.__init__() (#124225)

Free 'self->stat_atopen' before assigning it, since
io.FileIO.__init__() can be called multiple times manually
(especially by test_io).

diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 865b0e3634f3b4e9579148aa5aadb955bc2ccf07..8dae465fd20f8b09dccbfb5692398969838ba47b 100644 (file)
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -457,6 +457,7 @@ _io_FileIO___init___impl(fileio *self, PyObject *nameobj, const char *mode,
 #endif
     }
 
+    PyMem_Free(self->stat_atopen);
     self->stat_atopen = PyMem_New(struct _Py_stat_struct, 1);
     if (self->stat_atopen == NULL) {
         PyErr_NoMemory();