From: zhanghailiang <zhang.zhanghailiang@huawei.com>
Date: Tue, 5 Apr 2016 03:43:55 +0000 (+0800)
Subject: filter-buffer: fix segfault when starting qemu with status=off property
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=e0a039e50d481dce6b4ee45a29002538a258cd89;p=qmiga%2Fqemu.git

filter-buffer: fix segfault when starting qemu with status=off property

After commit 338d3f, we support 'status' property for filter object.
The segfault can be triggered by starting qemu with 'status=off' property
for filter, when the s->incoming_queue is NULL, we reference it directly
in qemu_net_queue_flush() which was called in status_changed() callback
function.

We shouldn't trigger status_changed() before the filter was initialized,
We can check the value of 'nf->netdev' to confirm if the filter is
initialized or not, so let's check its value before calling
status_changed().

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---

diff --git a/net/filter.c b/net/filter.c
index 1c4fc5a2c7..8ac79f3b7b 100644
--- a/net/filter.c
+++ b/net/filter.c
@@ -164,7 +164,7 @@ static void netfilter_set_status(Object *obj, const char *str, Error **errp)
         return;
     }
     nf->on = !nf->on;
-    if (nfc->status_changed) {
+    if (nf->netdev && nfc->status_changed) {
         nfc->status_changed(nf, errp);
     }
 }