[PATCH 2/8] virtio-net: Fix memory leak of vmstate_virtio_net_rss

[g00517791 <gaojinhao@huawei.com>]

From: Jinhao Gao <gaojinhao@huawei.com>

When VM migrate VMState of virtio-net-device/rss, the field(rss_data.
indirections_table) of virtio-net-device/rss having a flag of VMS_ALLOC
needs to allocate memory. If the dst doesn't free memory which has bee
n allocated for SaveStateEntry of virtio-net-device/rss before dst loads
device state, it may result that the pointer of rss_data.indirections_table
is overlaid when vm loads. We add the pre_load func to free memory, which
prevents memory leak.

Signed-off-by: Jinhao Gao <gaojinhao@huawei.com>
---
 hw/net/virtio-net.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 044ac95f6f..102e51f32f 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2957,11 +2957,22 @@ static bool virtio_net_rss_needed(void *opaque)
     return VIRTIO_NET(opaque)->rss_data.enabled;
 }
 
+static int virtio_net_rss_pre_load(void *opaque)
+{
+    VirtIONet *n = VIRTIO_NET(opaque);
+
+    g_free(n->rss_data.indirections_table);
+    n->rss_data.indirections_table = NULL;
+    n->rss_data.indirections_len = 0;
+    return 0;
+}
+
 static const VMStateDescription vmstate_virtio_net_rss = {
     .name      = "virtio-net-device/rss",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = virtio_net_rss_needed,
+    .pre_load = virtio_net_rss_pre_load,
     .fields = (VMStateField[]) {
         VMSTATE_BOOL(rss_data.enabled, VirtIONet),
         VMSTATE_BOOL(rss_data.redirect, VirtIONet),
-- 
2.23.0