Created attachment 1331977 [details]
logs

Description of problem:
RestAPI - get disks request failed with GetAllDisksWithSnapshotsQueryException: java.lang.NullPointerException.

 - GET request content is --  url:https://jenkins-vm-08.qa.lab.tlv.redhat.com/ovirt-engine/api/disks 

Version-Release number of selected component (if applicable):
Engine:
ovirt-engine-4.2.0-0.0.master.20170925172449.git9d850a9.el7.centos.noarch

VDSM:
vdsm-python-4.20.3-95.git0813890.el7.centos.noarch



How reproducible:
Happened once in a VERY long tier2 (24) run


Steps to Reproduce:
During tier 2 very long multiple tests issues occurred between tests.
No clear scenario to why this happened.

1. Rest API GET request content is --  url:https://jenkins-vm-08.qa.lab.tlv.redhat.com/ovirt-engine/api/disks 


Actual results:
ERROR - Response code is not valid, expected is: [200, 201], actual is: 500 

No issues are seen in VDSM but java.lang.NullPointerException occurs on engine log:

2017-09-27 18:01:47,633+03 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (default task-8) [hosts_update_b4a46b1f-fb66-4516] EVENT_ID: USER_UPDATE_VDS(43), Host host_mixed_3 configu
ration was updated by admin@internal-authz.
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2017-09-27 18:01:54,997+03 ERROR [org.ovirt.engine.core.bll.storage.disk.GetAllDisksWithSnapshotsQuery] (default task-14) [7b53a1b8-e643-420c-9cd4-586b1c2fa1dd] Query 'GetAllDisksWithSnapshotsQuery' failed: null
2017-09-27 18:01:54,997+03 ERROR [org.ovirt.engine.core.bll.storage.disk.GetAllDisksWithSnapshotsQuery] (default task-14) [7b53a1b8-e643-420c-9cd4-586b1c2fa1dd] Exception: java.lang.NullPointerException
        at org.ovirt.engine.core.bll.storage.disk.image.ImagesHandler.lambda$aggregateDiskImagesSnapshots$7(ImagesHandler.java:567) [bll.jar:]
        at java.util.ArrayList.forEach(ArrayList.java:1249) [rt.jar:1.8.0_144]
        at org.ovirt.engine.core.bll.storage.disk.image.ImagesHandler.aggregateDiskImagesSnapshots(ImagesHandler.java:565) [bll.jar:]
        at org.ovirt.engine.core.bll.storage.disk.GetAllDisksWithSnapshotsQuery.aggregateDisksSnapshots(GetAllDisksWithSnapshotsQuery.java:54) [bll.jar:]
        at org.ovirt.engine.core.bll.storage.disk.GetAllDisksWithSnapshotsQuery.executeQueryCommand(GetAllDisksWithSnapshotsQuery.java:36) [bll.jar:]
        at org.ovirt.engine.core.bll.QueriesCommandBase.executeCommand(QueriesCommandBase.java:106) [bll.jar:]
        at org.ovirt.engine.core.dal.VdcCommandBase.execute(VdcCommandBase.java:33) [dal.jar:]
        at org.ovirt.engine.core.bll.executor.DefaultBackendQueryExecutor.execute(DefaultBackendQueryExecutor.java:14) [bll.jar:]
        at org.ovirt.engine.core.bll.Backend.runQueryImpl(Backend.java:570) [bll.jar:]
        at org.ovirt.engine.core.bll.Backend.runQuery(Backend.java:539) [bll.jar:]
        at sun.reflect.GeneratedMethodAccessor116.invoke(Unknown Source) [:1.8.0_144]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_144]
        at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_144]
        at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:422)
        at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:509)
        at org.jboss.as.weld.ejb.DelegatingInterceptorInvocationContext.proceed(DelegatingInterceptorInvocationContext.java:92) [wildfly-weld-ejb-11.0.0.CR1.jar:11.0.0.CR1]
        at org.jboss.weld.interceptor.proxy.WeldInvocationContext.interceptorChainCompleted(WeldInvocationContext.java:98) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.jboss.weld.interceptor.proxy.WeldInvocationContext.proceed(WeldInvocationContext.java:117) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.ovirt.engine.core.common.di.interceptor.LoggingInterceptor.apply(LoggingInterceptor.java:12) [common.jar:]
        at sun.reflect.GeneratedMethodAccessor68.invoke(Unknown Source) [:1.8.0_144]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_144]
        at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_144]
        at org.jboss.weld.interceptor.reader.SimpleInterceptorInvocation$SimpleMethodInvocation.invoke(SimpleInterceptorInvocation.java:73) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.jboss.weld.interceptor.proxy.WeldInvocationContext.invokeNext(WeldInvocationContext.java:83) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.jboss.weld.interceptor.proxy.WeldInvocationContext.proceed(WeldInvocationContext.java:115) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.jboss.weld.bean.InterceptorImpl.intercept(InterceptorImpl.java:108) [weld-core-impl-2.4.3.Final.jar:2.4.3.Final]
        at org.jboss.as.weld.ejb.DelegatingInterceptorInvocationContext.proceed(DelegatingInterceptorInvocationContext.java:82) [wildfly-weld-ejb-11.0.0.CR1.jar:11.0.0.CR1]
        at org.jboss.as.weld.interceptors.EjbComponentInterceptorSupport.delegateInterception(EjbComponentInterceptorSupport.java:60)
        at org.jboss.as.weld.interceptors.Jsr299BindingsInterceptor.delegateInterception(Jsr299BindingsInterceptor.java:76)
        at org.jboss.as.weld.interceptors.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:88)
        at org.jboss.as.weld.interceptors.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:101)
        at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:63)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:422)
        at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:509)
        at org.ovirt.engine.core.bll.interceptors.CorrelationIdTrackerInterceptor.aroundInvoke(CorrelationIdTrackerInterceptor.java:13) [bll.jar:]
        at sun.reflect.GeneratedMethodAccessor69.invoke(Unknown Source) [:1.8.0_144]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_144]
        at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_144]
        at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptor.java:89)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:422)
        at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43) [wildfly-ejb3-11.0.0.CR1.jar:11.0.0.CR1]

Expected results:


Additional info: