[libvirt] [PATCH] Fix race condition in abort of stream
From: "Daniel P. Berrange" <berrange(a)redhat.com>
If a stream gets a server initiated abort, the client may still
send an abort request before it receives the server side abort.
This causes the server to send back another abort for the
stream. Since the protocol defines that abort is the last thing
to be sent, the client gets confused by this second abort from
the server. If the stream is already shutdown, just drop any
client requested abort, rather than sending back another message.
This fixes the regression from previous versions.
Tested as follows
In one virsh session
virsh # start foo
virsh # console foo
In other virsh session
virsh # destroy foo
The first virsh session should be able to continue issues
commands without error. Prior to this patch it saw
virsh # list
error: Failed to list active domains
error: An error occurred, but the cause is unknown
virsh # list
error: Failed to list active domains
error: no call waiting for reply with prog 536903814 vers 1 serial 9
* src/rpc/virnetserverprogram.c: Drop abort requests
for streams which no longer exist
---
src/rpc/virnetserverprogram.c | 25 ++++++++-----------------
1 files changed, 8 insertions(+), 17 deletions(-)
diff --git a/src/rpc/virnetserverprogram.c b/src/rpc/virnetserverprogram.c
index 63a6b6d..ca80ae0 100644
--- a/src/rpc/virnetserverprogram.c
+++ b/src/rpc/virnetserverprogram.c
@@ -257,23 +257,14 @@ int virNetServerProgramDispatch(virNetServerProgramPtr prog,
* stream packets after we closed down a stream. Just drop & ignore
* these.
*/
- if (msg->header.status == VIR_NET_CONTINUE) {
- VIR_INFO("Ignoring unexpected stream data serial=%d proc=%d
status=%d",
- msg->header.serial, msg->header.proc, msg->header.status);
- /* Send a dummy reply to free up 'msg' & unblock client rx */
- memset(msg, 0, sizeof(*msg));
- msg->header.type = VIR_NET_REPLY;
- if (virNetServerClientSendMessage(client, msg) < 0) {
- ret = -1;
- goto cleanup;
- }
- } else {
- VIR_INFO("Unexpected stream control message serial=%d proc=%d
status=%d",
- msg->header.serial, msg->header.proc, msg->header.status);
- virNetError(VIR_ERR_RPC,
- _("Unexpected stream control message serial=%d proc=%d
status=%d"),
- msg->header.serial, msg->header.proc,
msg->header.status);
- goto error;
+ VIR_INFO("Ignoring unexpected stream data serial=%d proc=%d
status=%d",
+ msg->header.serial, msg->header.proc, msg->header.status);
+ /* Send a dummy reply to free up 'msg' & unblock client rx */
+ memset(msg, 0, sizeof(*msg));
+ msg->header.type = VIR_NET_REPLY;
+ if (virNetServerClientSendMessage(client, msg) < 0) {
+ ret = -1;
+ goto cleanup;
}
ret = 0;
break;
--
1.7.6