[PATCH 8/8] dbus-vmstate: Fix memory leak of dbus_vmstate

From: g00517791 <gaojinhao@huawei.com>
To: <qemu-devel@nongnu.org>, <qemu-ppc@nongnu.org>
Cc: "Michael S . Tsirkin" <mst@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Stefan Berger" <stefanb@linux.vnet.ibm.com>,
	"Greg Kurz" <groug@kaod.org>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	"Juan Quintela" <quintela@redhat.com>,
	wanghaibin.wang@huawei.com,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	zhukeqian1@huawei.com,
	"David Gibson" <david@gibson.dropbear.id.au>
Subject: [PATCH 8/8] dbus-vmstate: Fix memory leak of dbus_vmstate
Date: Sat, 26 Dec 2020 18:33:47 +0800	[thread overview]
Message-ID: <20201226103347.868-9-gaojinhao@huawei.com> (raw)
In-Reply-To: <20201226103347.868-1-gaojinhao@huawei.com>

From: Jinhao Gao <gaojinhao@huawei.com>

When VM migrate VMState of dbus_vmstate, the field(data) of
dbus_vmstate having a flag of VMS_ALLOC needs to allocate memory.
If the dst doesn't free memory which has been allocated for
SaveStateEntry of dbus_vmstate before dst loads device state, it may
result that the pointer of data 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>
---
 backends/dbus-vmstate.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/backends/dbus-vmstate.c b/backends/dbus-vmstate.c
index bd050e8e9c..c13fbee760 100644
--- a/backends/dbus-vmstate.c
+++ b/backends/dbus-vmstate.c
@@ -366,10 +366,21 @@ static int dbus_vmstate_pre_save(void *opaque)
     return 0;
 }
 
+static int dbus_vmstate_pre_load(void *opaque)
+{
+    DBusVMState *self = DBUS_VMSTATE(opaque);
+
+    g_free(self->data);
+    self->data = NULL;
+    self->data_size = 0;
+    return 0;
+}
+
 static const VMStateDescription dbus_vmstate = {
     .name = TYPE_DBUS_VMSTATE,
     .version_id = 0,
     .pre_save = dbus_vmstate_pre_save,
+    .pre_load = dbus_vmstate_pre_load,
     .post_load = dbus_vmstate_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(data_size, DBusVMState),
-- 
2.23.0


