[libvirt] [PATCH] Fix buzzilla 738778

[Stefan Berger]

This patch fixes the bug shown in bugzilla 738778. It's not an nwfilter 
problem but a connection sharing / closure issue.

https://bugzilla.redhat.com/show_bug.cgi?id=738778

Depending on the speed / #CPUs of the machine you are using you may not 
see this bug all the time.

Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index f8a8475..1991777 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2539,6 +2539,10 @@ struct qemuProcessReconnectData {
  /*
   * Open an existing VM's monitor, re-detect VCPU threads
   * and re-reserve the security labels in use
+ *
+ * We own the virConnectPtr we are passed here - whoever started
+ * this thread function has increased the reference counter to it
+ * so that we now have to close it.
   */
  static void
  qemuProcessReconnect(void *opaque)
@@ -2632,6 +2636,8 @@ qemuProcessReconnect(void *opaque)

      qemuDriverUnlock(driver);

+    virConnectClose(conn);
+
      return;

  error:
@@ -2656,6 +2662,8 @@ error:
              virDomainObjUnlock(obj);
      }
      qemuDriverUnlock(driver);
+
+    virConnectClose(conn);
  }

  static void
@@ -2706,7 +2714,16 @@ qemuProcessReconnectHelper(void *payload,
      if (qemuDomainObjBeginJobWithDriver(src->driver, obj, 
QEMU_JOB_MODIFY) < 0)
          goto error;

+    /* Since we close the connection later on, we have to make sure
+     * that the threads we start see a valid connection throughout their
+     * lifetime. We simply increase the reference counter here.
+     */
+    virConnectRef(data->conn);
+
      if (virThreadCreate(&thread, true, qemuProcessReconnect, data) < 0) {
+
+        virConnectClose(data->conn);
+
          qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                          _("Could not create thread. QEMU initialization "
                            "might be incomplete"));