RETURN_STRING() did not use Py_INCREF() when returning Py_None

David Sommerseth · David Sommerseth · commit aa2c20e697af · 2011-02-25T09:57:04.000+01:00
From RH BZ#680269:

     #define RETURN_STRING(str) (str ? PyString_FromString(str) : Py_None)

  This isn't incrementing the reference count on the Py_None singleton when it
  should be (the caller assumes that it "owns" a ref on the result of _getter,
  and will decref it), it could cause the python process to bail out:
    "Fatal Python error: deallocating None"
  if run repeatedly.

Reported-by: Dave Malcolm &lt;dmalcolm@redhat.com&gt;
Signed-off-by: David Sommerseth &lt;davids@redhat.com&gt;
diff --git a/python-ethtool/etherinfo_struct.h b/python-ethtool/etherinfo_struct.h
@@ -87,6 +87,6 @@ typedef struct {
  *
  * @return Returns a PyObject with either the input string wrapped up, or a Python None value.
  */
-#define RETURN_STRING(str) (str ? PyString_FromString(str) : Py_None)
+#define RETURN_STRING(str) (str ? PyString_FromString(str) : (Py_INCREF(Py_None), Py_None))
 
 #endif

Original file line number	Diff line number	Diff line change
`@@ -87,6 +87,6 @@ typedef struct {`
`87`	`87`	`*`
`88`	`88`	`* @return Returns a PyObject with either the input string wrapped up, or a Python None value.`
`89`	`89`	`*/`
`90`		`-#define RETURN_STRING(str) (str ? PyString_FromString(str) : Py_None)`
	`90`	`+#define RETURN_STRING(str) (str ? PyString_FromString(str) : (Py_INCREF(Py_None), Py_None))`
`91`	`91`
`92`	`92`	`#endif`