File libvirt-Fix-race-in-starting-transient-VMs.patch of Package libvirt

From 62603aedb52205b53be6ecf85edd10bc25216c5f Mon Sep 17 00:00:00 2001
Message-Id: <62603aedb52205b53be6ecf85edd10bc25216c5f@dist-git>
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Wed, 6 Nov 2013 15:16:31 +0100
Subject: [PATCH] Fix race in starting transient VMs

https://bugzilla.redhat.com/show_bug.cgi?id=1022924

When starting a transient VM the first thing done is to check
for duplicates. The check looks if there are any running VMs
with the matching name/uuid. It explicitly allows there to
be inactive VMs, so that a persistent VM can be temporarily
booted with a different config.

There is a race condition, however, where 2 or more clients
try to create the same transient VM. The first client will
cause a virDomainObjPtr to be added to the domain list, and
it is inactive at this stage. The second client may then
come along and see this inactive VM, and mistake it for a
persistent VM.

If the first VM fails to start its transient guest for any
reason, then it'll remove the virDomainObjPtr from the list.
The second client now has a virDomainObjPtr that it can try
to boot, which libvirt no longer has a record of. The result
can be a running QEMU process that is orphaned.

It was also, however, possible for the virDomainObjPtr to be
completely free'd which will cause libvirtd to crash in some
scenarios.

The fix is to only allow an existing inactive VM if it is
marked as persistent.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 89759301dea870ee80f2ca74751db589e8f7b593)

Conflicts:
	src/conf/domain_conf.c: The code in 6.5 is not rebased and therefore
    completely different to the upstream that has been cherry picked
    from.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/conf/domain_conf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 6937a1f..a63755b 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -14898,7 +14898,13 @@ virDomainObjIsDuplicate(virDomainObjListPtr doms,
             /* UUID & name match, but if VM is already active, refuse it */
             if (virDomainObjIsActive(vm)) {
                 virReportError(VIR_ERR_OPERATION_INVALID,
-                               _("domain is already active as '%s'"),
+                               _("domain '%s' is already active"),
+                               vm->def->name);
+                goto cleanup;
+            }
+            if (!vm->persistent) {
+                virReportError(VIR_ERR_OPERATION_INVALID,
+                               _("domain '%s' is already being started"),
                                vm->def->name);
                 goto cleanup;
             }
-- 
1.9.1