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rpc: invoke the message dispatch callback with client unlocked
Currently if the virNetServer instance is created with max_workers==0 to request a non-threaded dispatch process, we deadlock during dispatch #0 0x00007fb845f6f42d in __lll_lock_wait () from /lib64/libpthread.so.0 #1 0x00007fb845f681d3 in pthread_mutex_lock () from /lib64/libpthread.so.0 #2 0x000055a6628bb305 in virMutexLock (m=<optimized out>) at util/virthread.c:89 #3 0x000055a6628a984b in virObjectLock (anyobj=<optimized out>) at util/virobject.c:435 #4 0x000055a66286fcde in virNetServerClientIsAuthenticated (client=client@entry=0x55a663a7b960) at rpc/virnetserverclient.c:1565 #5 0x000055a66286cc17 in virNetServerProgramDispatchCall (msg=0x55a663a7bc50, client=0x55a663a7b960, server=0x55a663a77550, prog=0x55a663a78020) at rpc/virnetserverprogram.c:407 #6 virNetServerProgramDispatch (prog=prog@entry=0x55a663a78020, server=server@entry=0x55a663a77550, client=client@entry=0x55a663a7b960, msg=msg@entry=0x55a663a7bc50) at rpc/virnetserverprogram.c:307 #7 0x000055a662871d56 in virNetServerProcessMsg (msg=0x55a663a7bc50, prog=0x55a663a78020, client=0x55a663a7b960, srv=0x55a663a77550) at rpc/virnetserver.c:148 #8 virNetServerDispatchNewMessage (client=0x55a663a7b960, msg=0x55a663a7bc50, opaque=0x55a663a77550) at rpc/virnetserver.c:227 #9 0x000055a66286e4c0 in virNetServerClientDispatchRead (client=client@entry=0x55a663a7b960) at rpc/virnetserverclient.c:1322 #10 0x000055a66286e813 in virNetServerClientDispatchEvent (sock=<optimized out>, events=1, opaque=0x55a663a7b960) at rpc/virnetserverclient.c:1507 #11 0x000055a662899be0 in virEventPollDispatchHandles (fds=0x55a663a7bdc0, nfds=<optimized out>) at util/vireventpoll.c:508 #12 virEventPollRunOnce () at util/vireventpoll.c:657 #13 0x000055a6628982f1 in virEventRunDefaultImpl () at util/virevent.c:327 #14 0x000055a6628716d5 in virNetDaemonRun (dmn=0x55a663a771b0) at rpc/virnetdaemon.c:858 #15 0x000055a662864c1d in main (argc=<optimized out>, #argv=0x7ffd105b4838) at logging/log_daemon.c:1235 Reviewed-by: John Ferlan <jferlan@redhat.com> Reviewed-by: Jim Fehlig <jfehlig@suse.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrangé
parent
c6f1d5190b
commit
06e7ebb608
@ -143,7 +143,7 @@ VIR_ONCE_GLOBAL_INIT(virNetServerClient)
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static void virNetServerClientDispatchEvent(virNetSocketPtr sock, int events, void *opaque);
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static void virNetServerClientUpdateEvent(virNetServerClientPtr client);
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static void virNetServerClientDispatchRead(virNetServerClientPtr client);
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static virNetMessagePtr virNetServerClientDispatchRead(virNetServerClientPtr client);
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static int virNetServerClientSendMessageLocked(virNetServerClientPtr client,
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virNetMessagePtr msg);
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@ -340,18 +340,40 @@ virNetServerClientCheckAccess(virNetServerClientPtr client)
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}
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#endif
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static void virNetServerClientDispatchMessage(virNetServerClientPtr client,
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virNetMessagePtr msg)
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{
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virObjectLock(client);
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if (!client->dispatchFunc) {
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virNetMessageFree(msg);
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client->wantClose = true;
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virObjectUnlock(client);
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} else {
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virObjectUnlock(client);
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/* Accessing 'client' is safe, because virNetServerClientSetDispatcher
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* only permits setting 'dispatchFunc' once, so if non-NULL, it will
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* never change again
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*/
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client->dispatchFunc(client, msg, client->dispatchOpaque);
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}
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}
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static void virNetServerClientSockTimerFunc(int timer,
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void *opaque)
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{
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virNetServerClientPtr client = opaque;
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virNetMessagePtr msg = NULL;
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virObjectLock(client);
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virEventUpdateTimeout(timer, -1);
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/* Although client->rx != NULL when this timer is enabled, it might have
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* changed since the client was unlocked in the meantime. */
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if (client->rx)
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virNetServerClientDispatchRead(client);
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msg = virNetServerClientDispatchRead(client);
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virObjectUnlock(client);
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if (msg)
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virNetServerClientDispatchMessage(client, msg);
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}
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@ -950,8 +972,13 @@ void virNetServerClientSetDispatcher(virNetServerClientPtr client,
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void *opaque)
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{
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virObjectLock(client);
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client->dispatchFunc = func;
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client->dispatchOpaque = opaque;
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/* Only set dispatcher if not already set, to avoid race
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* with dispatch code that runs without locks held
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*/
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if (!client->dispatchFunc) {
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client->dispatchFunc = func;
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client->dispatchOpaque = opaque;
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}
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virObjectUnlock(client);
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}
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@ -1196,26 +1223,32 @@ static ssize_t virNetServerClientRead(virNetServerClientPtr client)
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/*
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* Read data until we get a complete message to process
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* Read data until we get a complete message to process.
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* If a complete message is available, it will be returned
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* from this method, for dispatch by the caller.
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*
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* Returns a complete message for dispatch, or NULL if none is
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* yet available, or an error occurred. On error, the wantClose
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* flag will be set.
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*/
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static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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static virNetMessagePtr virNetServerClientDispatchRead(virNetServerClientPtr client)
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{
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readmore:
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if (client->rx->nfds == 0) {
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if (virNetServerClientRead(client) < 0) {
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client->wantClose = true;
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return; /* Error */
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return NULL; /* Error */
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}
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}
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if (client->rx->bufferOffset < client->rx->bufferLength)
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return; /* Still not read enough */
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return NULL; /* Still not read enough */
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/* Either done with length word header */
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if (client->rx->bufferLength == VIR_NET_MESSAGE_LEN_MAX) {
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if (virNetMessageDecodeLength(client->rx) < 0) {
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client->wantClose = true;
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return;
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return NULL;
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}
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virNetServerClientUpdateEvent(client);
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@ -1236,7 +1269,7 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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virNetMessageQueueServe(&client->rx);
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virNetMessageFree(msg);
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client->wantClose = true;
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return;
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return NULL;
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}
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/* Now figure out if we need to read more data to get some
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@ -1246,7 +1279,7 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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virNetMessageQueueServe(&client->rx);
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virNetMessageFree(msg);
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client->wantClose = true;
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return; /* Error */
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return NULL; /* Error */
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}
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/* Try getting the file descriptors (may fail if blocking) */
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@ -1256,7 +1289,7 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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virNetMessageQueueServe(&client->rx);
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virNetMessageFree(msg);
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client->wantClose = true;
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return;
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return NULL;
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}
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if (rv == 0) /* Blocking */
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break;
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@ -1270,7 +1303,7 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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* again next time we run this method
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*/
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client->rx->bufferOffset = client->rx->bufferLength;
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return;
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return NULL;
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}
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}
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@ -1313,16 +1346,6 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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}
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}
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/* Send off to for normal dispatch to workers */
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if (msg) {
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if (!client->dispatchFunc) {
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virNetMessageFree(msg);
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client->wantClose = true;
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} else {
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client->dispatchFunc(client, msg, client->dispatchOpaque);
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}
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}
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/* Possibly need to create another receive buffer */
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if (client->nrequests < client->nrequests_max) {
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if (!(client->rx = virNetMessageNew(true))) {
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@ -1338,6 +1361,8 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
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}
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}
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virNetServerClientUpdateEvent(client);
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return msg;
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}
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}
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@ -1482,6 +1507,7 @@ static void
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virNetServerClientDispatchEvent(virNetSocketPtr sock, int events, void *opaque)
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{
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virNetServerClientPtr client = opaque;
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virNetMessagePtr msg = NULL;
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virObjectLock(client);
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@ -1504,7 +1530,7 @@ virNetServerClientDispatchEvent(virNetSocketPtr sock, int events, void *opaque)
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virNetServerClientDispatchWrite(client);
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if (events & VIR_EVENT_HANDLE_READABLE &&
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client->rx)
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virNetServerClientDispatchRead(client);
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msg = virNetServerClientDispatchRead(client);
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#if WITH_GNUTLS
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}
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#endif
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@ -1517,6 +1543,9 @@ virNetServerClientDispatchEvent(virNetSocketPtr sock, int events, void *opaque)
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client->wantClose = true;
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virObjectUnlock(client);
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if (msg)
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virNetServerClientDispatchMessage(client, msg);
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}
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