From: Peter Krempa <pkrempa@redhat.com>
Date: Tue, 27 Oct 2015 06:29:53 +0000 (+0100)
Subject: qemu: qemuDomainSetVcpusAgent: re-check agent before calling it the again
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=2642a36db5d54bc4507e601f4e7bac8de7618129;p=people%2Fliuw%2Flibxenctrl-split%2Flibvirt.git

qemu: qemuDomainSetVcpusAgent: re-check agent before calling it the again

With a very unfortunate timing, the agent might vanish before we do the
second call while the locks were down. Re-check that the agent is
available before attempting it again.
---

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 62f105439..7a99ed244 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4881,6 +4881,9 @@ qemuDomainSetVcpusAgent(virDomainObjPtr vm,
     if (qemuAgentUpdateCPUInfo(nvcpus, cpuinfo, ncpuinfo) < 0)
         goto cleanup;
 
+    if (!qemuDomainAgentAvailable(vm, true))
+        goto cleanup;
+
     qemuDomainObjEnterAgent(vm);
     ret = qemuAgentSetVCPUs(qemuDomainGetAgent(vm), cpuinfo, ncpuinfo);
     qemuDomainObjExitAgent(vm);