[libvirt] [PATCHv2] python: Avoid memory leaks on libvirt_virNodeGetMemoryStats
Eric Blake
eblake at redhat.com
Tue Feb 14 13:14:30 UTC 2012
On 02/14/2012 04:19 AM, ajia at redhat.com wrote:
> From: Alex Jia <ajia at redhat.com>
>
> Detected by valgrind. Leaks are introduced in commit 17c7795.
>
> * python/libvirt-override.c (libvirt_virNodeGetMemoryStats): fix memory leaks
> and improve codes return value.
>
> For details, please see the following link:
> RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=770944
>
> Signed-off-by: Alex Jia <ajia at redhat.com>
> ---
> python/libvirt-override.c | 43 +++++++++++++++++++++++++++++--------------
> 1 files changed, 29 insertions(+), 14 deletions(-)
>
> diff --git a/python/libvirt-override.c b/python/libvirt-override.c
> index 4e8a97e..594aae6 100644
> --- a/python/libvirt-override.c
> +++ b/python/libvirt-override.c
> @@ -2426,7 +2426,9 @@ libvirt_virNodeGetCPUStats(PyObject *self ATTRIBUTE_UNUSED, PyObject *args)
> static PyObject *
> libvirt_virNodeGetMemoryStats(PyObject *self ATTRIBUTE_UNUSED, PyObject *args)
> {
> - PyObject *ret;
> + PyObject *ret = VIR_PY_NONE;
NAK - this increments the reference count on the None object...
> + PyObject *key = NULL;
> + PyObject *val = NULL;
> PyObject *pyobj_conn;
> virConnectPtr conn;
> unsigned int flags;
> @@ -2442,32 +2444,45 @@ libvirt_virNodeGetMemoryStats(PyObject *self ATTRIBUTE_UNUSED, PyObject *args)
> c_retval = virNodeGetMemoryStats(conn, cellNum, NULL, &nparams, flags);
> LIBVIRT_END_ALLOW_THREADS;
> if (c_retval < 0)
> - return VIR_PY_NONE;
> + return ret;
>
> if (nparams) {
> if (VIR_ALLOC_N(stats, nparams) < 0)
> - return VIR_PY_NONE;
> + return PyErr_NoMemory();
...but this fails to decrement the reference count, so you've leaked a
resource. See my comments on v1.
> +
> + if (PyDict_SetItem(ret, key, val) < 0) {
> + Py_DECREF(ret);
> + goto error;
And here, you have a python exception from PyDict_SetItem...
> + }
> +
> + Py_DECREF(key);
> + Py_DECREF(val);
> }
>
> VIR_FREE(stats);
> return ret;
> +
> +error:
> + VIR_FREE(stats);
> + Py_XDECREF(key);
> + Py_XDECREF(val);
> + return ret;
...so here, you _want_ to return NULL, not VIR_PY_NONE.
--
Eric Blake eblake at redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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