From 9ffcbf71a52bcca74022fb58f56b145ff6af7f97 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Charles-Fran=C3=A7ois=20Natali?= Date: Thu, 6 Oct 2011 19:09:45 +0200 Subject: [PATCH] Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle would be finalized after the reference to its underlying BufferedRWPair's writer got cleared by the GC. --- Lib/test/test_io.py | 15 +++++++++++++++ Misc/NEWS | 4 ++++ Modules/_io/bufferedio.c | 5 +++++ 3 files changed, 24 insertions(+) diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py index 608fc414ca1..003a4f34bad 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -2338,6 +2338,21 @@ class CTextIOWrapperTest(TextIOWrapperTest): with self.open(support.TESTFN, "rb") as f: self.assertEqual(f.read(), b"456def") + def test_rwpair_cleared_before_textio(self): + # Issue 13070: TextIOWrapper's finalization would crash when called + # after the reference to the underlying BufferedRWPair's writer got + # cleared by the GC. + for i in range(1000): + b1 = self.BufferedRWPair(self.MockRawIO(), self.MockRawIO()) + t1 = self.TextIOWrapper(b1, encoding="ascii") + b2 = self.BufferedRWPair(self.MockRawIO(), self.MockRawIO()) + t2 = self.TextIOWrapper(b2, encoding="ascii") + # circular references + t1.buddy = t2 + t2.buddy = t1 + support.gc_collect() + + class PyTextIOWrapperTest(TextIOWrapperTest): pass diff --git a/Misc/NEWS b/Misc/NEWS index 71a346d6e9d..d89ef68e70f 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -217,6 +217,10 @@ Library Extension Modules ----------------- +- Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle + would be finalized after the reference to its underlying BufferedRWPair's + writer got cleared by the GC. + - Issue #12881: ctypes: Fix segfault with large structure field names. - Issue #13013: ctypes: Fix a reference leak in PyCArrayType_from_ctype. diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c index 73f924e8404..1b81647b49d 100644 --- a/Modules/_io/bufferedio.c +++ b/Modules/_io/bufferedio.c @@ -2179,6 +2179,11 @@ bufferedrwpair_isatty(rwpair *self, PyObject *args) static PyObject * bufferedrwpair_closed_get(rwpair *self, void *context) { + if (self->writer == NULL) { + PyErr_SetString(PyExc_RuntimeError, + "the BufferedRWPair object is being garbage-collected"); + return NULL; + } return PyObject_GetAttr((PyObject *) self->writer, _PyIO_str_closed); }