The following test failed in the JDK18 CI:

gc/g1/mixedgc/TestOldGenCollectionUsage.java

Here's a snippet from the log file:

#section:main
----------messages:(5/1128)----------
command: main -Xbootclasspath/a:. -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -verbose:gc -XX:NewSize=2m -XX:MaxNewSize=2m -Xmx14m -Xms14m -XX:+AlwaysTenure -XX:InitiatingHeapOccupancyPercent=100 -XX:-G1UseAdaptiveIHOP -XX:G1MixedGCCountTarget=4 -XX:MaxGCPauseMillis=30000 -XX:G1HeapRegionSize=1m -XX:G1HeapWastePercent=0 -XX:G1MixedGCLiveThresholdPercent=100 gc.g1.mixedgc.TestOldGenCollectionUsage
reason: User specified action: run main/othervm -Xbootclasspath/a:. -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -verbose:gc -XX:NewSize=2m -XX:MaxNewSize=2m -Xmx14m -Xms14m -XX:+AlwaysTenure -XX:InitiatingHeapOccupancyPercent=100 -XX:-G1UseAdaptiveIHOP -XX:G1MixedGCCountTarget=4 -XX:MaxGCPauseMillis=30000 -XX:G1HeapRegionSize=1m -XX:G1HeapWastePercent=0 -XX:G1MixedGCLiveThresholdPercent=100 gc.g1.mixedgc.TestOldGenCollectionUsage
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.base,java.management --add-exports java.base/jdk.internal.misc=ALL-UNNAMED
elapsed time (seconds): 0.424
----------configuration:(4/111)----------
Boot Layer
  add modules: java.base java.management
  add exports: java.base/jdk.internal.misc ALL-UNNAMED

----------System.out:(21/1277)----------
[0.007s][info][gc] Using G1
Monitor G1 Old Gen pool with G1 Young Generation collector.
Found pool: G1 Old Gen
Found collector: G1 Young Generation
[0.298s][info][gc] GC(0) Pause Young (Normal) (G1 Evacuation Pause) 2M->1M(16M) 2.067ms
[0.312s][info][gc] GC(1) Pause Full (WhiteBox Initiated Full GC) 1M->1M(16M) 9.335ms
[0.318s][info][gc] GC(2) Pause Young (Normal) (G1 Evacuation Pause) 3M->3M(16M) 1.416ms
[0.318s][info][gc] GC(3) Pause Young (Normal) (WhiteBox Initiated Young GC) 3M->3M(16M) 0.628ms
G1 Old Gen: usage after GC = 1786184
G1 Young Generation: collection count = 3
G1 Young Generation: collection time = 4
[0.333s][info][gc] GC(4) Pause Young (Concurrent Start) (WhiteBox Initiated Concurrent Mark) 3M->3M(16M) 0.470ms
[0.333s][info][gc] GC(5) Concurrent Mark Cycle
[0.339s][info][gc] GC(5) Pause Remark 3M->3M(16M) 2.340ms
[0.340s][info][gc] GC(5) Pause Cleanup 3M->3M(16M) 0.019ms
[0.340s][info][gc] GC(5) Concurrent Mark Cycle 6.666ms
[0.381s][info][gc] GC(6) Pause Young (Prepare Mixed) (WhiteBox Initiated Young GC) 3M->3M(16M) 0.268ms
[0.381s][info][gc] GC(7) Pause Young (Mixed) (WhiteBox Initiated Young GC) 3M->3M(16M) 0.241ms
G1 Old Gen: usage after GC = 3358024
G1 Young Generation: collection count = 6
G1 Young Generation: collection time = 4
----------System.err:(14/957)----------
java.lang.RuntimeException: Collector has not run some more
at gc.g1.mixedgc.TestOldGenCollectionUsage.run(TestOldGenCollectionUsage.java:143)
at gc.g1.mixedgc.TestOldGenCollectionUsage.main(TestOldGenCollectionUsage.java:62)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:833)

JavaTest Message: Test threw exception: java.lang.RuntimeException: Collector has not run some more
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: Collector has not run some more
----------rerun:(53/8901)*----------