[PATCH] python/xc: add missing Py_DECREF() to fix a memory leak

[Zhigang Wang <zhigang.x.wang@oracle.com>]

Python PyList_Append() will increase reference count of the item. We have to
decrease its reference count to let it garbage collected.

We missed the Py_DECREF() for 'cpuinfo_obj' here, thus we have a memory leak.

The memory leak could be easily confirmed by:

  # python
  >>> import xen.lowlevel.xc
  >>> xc = xen.lowlevel.xc.xc()
  >>> for i in range(1000): xc.getcpuinfo(1)

And check the python process memory usage before and after:

  # ps f -o vsize,rss,%mem,size,cmd -p <pid>

Signed-off-by: Zhigang Wang <zhigang.x.wang@oracle.com>
---
 tools/python/xen/lowlevel/xc/xc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/python/xen/lowlevel/xc/xc.c b/tools/python/xen/lowlevel/xc/xc.c
index 2c36eb2..9a161d3 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -1210,6 +1210,7 @@ static PyObject *pyxc_getcpuinfo(XcObject *self, PyObject *args, PyObject *kwds)
     for (i = 0; i < nr_cpus; i++) {
         cpuinfo_obj = Py_BuildValue("{s:k}", "idletime", cpuinfo_ptr->idletime);
         PyList_Append(cpuinfo_list_obj, cpuinfo_obj);
+        Py_DECREF(cpuinfo_obj);
         cpuinfo_ptr++;
     }
 
-- 
2.1.0