Backport:

Fix SF #762455, segfault when sys.stdout is changed in getattr

Note:  in 2.2, the problem was an infinite loop (at least for me).

1 files changed, 6 insertions, 0 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index d764b54..e8c14f8 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1365,6 +1365,11 @@ eval_frame(PyFrameObject *f)
 					err = -1;
 				}
 			}
+			/* PyFile_SoftSpace() can exececute arbitrary code
+			   if sys.stdout is an instance with a __getattr__.
+			   If __getattr__ raises an exception, w will
+			   be freed, so we need to prevent that temporarily. */
+			Py_XINCREF(w);
 			if (w != NULL && PyFile_SoftSpace(w, 1))
 				err = PyFile_WriteString(" ", w);
 			if (err == 0)
@@ -1390,6 +1395,7 @@ eval_frame(PyFrameObject *f)
 			    }
 #endif
 			}
+			Py_XDECREF(w);
 			Py_DECREF(v);
 			Py_XDECREF(stream);
 			stream = NULL;