Tal Nisan has submitted this change and it was merged. Change subject: core: prevent possible deadlock between monitoring threads ...................................................................... core: prevent possible deadlock between monitoring threads If VM went down during migration in the source host, the monitoring (VURTI) thread of the source host tries to destroy the VM in the destination host. In order to destroy the VM in the destination host, it tries to lock the destination host. When we have two monitoring threads that try to do it, we end-up in a deadlock because each of them locks the host it monitors and tries to lock the other one. This patch solves this problem by postponing the destroy operation on the destination host to take place after the lock on the monitored host is released. It is safe to do it that way because the status of the VM in the destination host must be either Down or MigratingTo. If the status is MigratingTo, the monitoring of the destination host just ignores the VM. If the status is Down, the monitoring of the destination host will just destroy the VM and the second destroy operation will fail. Change-Id: Ia4c52e0f8109f9599965078d2c6dd4db705cec97 Bug-Url: https://bugzilla.redhat.com/1142776 Signed-off-by: Arik Hadas <ahadas(a)redhat.com&gt; --- M backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/VdsEventListener.java M backend/manager/modules/common/src/main/java/org/ovirt/engine/core/common/businessentities/IVdsEventListener.java M backend/manager/modules/vdsbroker/src/main/java/org/ovirt/engine/core/vdsbroker/VdsUpdateRunTimeInfo.java 3 files changed, 35 insertions(+), 15 deletions(-) Approvals: Omer Frenkel: Looks good to me, approved Arik Hadas: Verified -- To view, visit http://gerrit.ovirt.org/35099 To unsubscribe, visit http://gerrit.ovirt.org/settings Gerrit-MessageType: merged Gerrit-Change-Id: Ia4c52e0f8109f9599965078d2c6dd4db705cec97 Gerrit-PatchSet: 1 Gerrit-Project: ovirt-engine Gerrit-Branch: ovirt-engine-3.5 Gerrit-Owner: Arik Hadas <ahadas(a)redhat.com&gt; Gerrit-Reviewer: Arik Hadas <ahadas(a)redhat.com&gt; Gerrit-Reviewer: Omer Frenkel <ofrenkel(a)redhat.com&gt; Gerrit-Reviewer: Tal Nisan <tnisan(a)redhat.com&gt; Gerrit-Reviewer: automation(a)ovirt.org Gerrit-Reviewer: oVirt Jenkins CI Server