[libvirt] [PATCH] Fix bug libvirt daemon segfault when new force console vm session break down existed console session. When force console vm command arrived, libvirtd will break down existed console session, and in this procedure, it will call daemonStreamEvent() to release resources , so daemonStreamFilter() need to check if stream filter existed when get client object lock and client->privData's lock, if not existed, just return -1

[LanceLiu]

---
 src/libvirt_remote.syms           |  1 +
 src/remote/remote_daemon_stream.c | 10 +++++++++-
 src/rpc/virnetserverclient.c      | 12 ++++++++++++
 src/rpc/virnetserverclient.h      |  2 ++
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/libvirt_remote.syms b/src/libvirt_remote.syms
index 0493467..c32e234 100644
--- a/src/libvirt_remote.syms
+++ b/src/libvirt_remote.syms
@@ -173,6 +173,7 @@ virNetServerClientPreExecRestart;
 virNetServerClientRemoteAddrStringSASL;
 virNetServerClientRemoteAddrStringURI;
 virNetServerClientRemoveFilter;
+virNetServerClientCheckFilterExist;
 virNetServerClientSendMessage;
 virNetServerClientSetAuthLocked;
 virNetServerClientSetAuthPendingLocked;
diff --git a/src/remote/remote_daemon_stream.c b/src/remote/remote_daemon_stream.c
index 82cadb6..de0dca3 100644
--- a/src/remote/remote_daemon_stream.c
+++ b/src/remote/remote_daemon_stream.c
@@ -292,10 +292,18 @@ daemonStreamFilter(virNetServerClientPtr client,
 {
     daemonClientStream *stream = opaque;
     int ret = 0;
+    daemonClientPrivatePtr priv = NULL;
+    int filter_id = stream->filterID;
 
     virObjectUnlock(client);
+    priv = virNetServerClientGetPrivateData(client);
     virMutexLock(&stream->priv->lock);
     virObjectLock(client);
+    if (!virNetServerClientCheckFilterExist(client, filter_id)) {
+        VIR_WARN("this daemon stream filter: %d have been deleted!", filter_id);
+        ret = -1;
+        goto cleanup;
+    }
 
     if (msg->header.type != VIR_NET_STREAM &&
         msg->header.type != VIR_NET_STREAM_HOLE)
@@ -317,7 +325,7 @@ daemonStreamFilter(virNetServerClientPtr client,
     ret = 1;
 
  cleanup:
-    virMutexUnlock(&stream->priv->lock);
+    virMutexUnlock(&priv->lock);
     return ret;
 }
 
diff --git a/src/rpc/virnetserverclient.c b/src/rpc/virnetserverclient.c
index 67b3bf9..f80f493 100644
--- a/src/rpc/virnetserverclient.c
+++ b/src/rpc/virnetserverclient.c
@@ -287,6 +287,18 @@ void virNetServerClientRemoveFilter(virNetServerClientPtr client,
     virObjectUnlock(client);
 }
 
+int virNetServerClientCheckFilterExist(virNetServerClientPtr client,
+                                       int filterID)
+{
+    virNetServerClientFilterPtr tmp;
+
+    tmp = client->filters;
+    while(tmp && tmp->id != filterID) {
+        tmp = tmp->next;
+    }
+
+    return (tmp != NULL);
+}
 
 /* Check the client's access. */
 static int
diff --git a/src/rpc/virnetserverclient.h b/src/rpc/virnetserverclient.h
index 7a3061d..85fda39 100644
--- a/src/rpc/virnetserverclient.h
+++ b/src/rpc/virnetserverclient.h
@@ -93,6 +93,8 @@ int virNetServerClientAddFilter(virNetServerClientPtr client,
 
 void virNetServerClientRemoveFilter(virNetServerClientPtr client,
                                     int filterID);
+int virNetServerClientCheckFilterExist(virNetServerClientPtr client,
+                                       int filterID);
 
 int virNetServerClientGetAuth(virNetServerClientPtr client);
 void virNetServerClientSetAuthLocked(virNetServerClientPtr client, int auth);
-- 
1.8.3.1