The following test failed in the JDK19 CI:

vmTestbase/jit/graph/cgt0.java

This test failed in the COMPILE phase with these error msgs:

#section:build
----------messages:(5/528)----------
command: build jit.graph.*
reason: User specified action: run build jit.graph.*
Library /vmTestbase:
  compile: jit.graph.test3, jit.graph.cgt3, jit.graph.Node, jit.graph.test2, jit.graph.cgt2, jit.graph.MethodData, jit.graph.cgt9, jit.graph.cgt5, jit.graph.test5, jit.graph.cgt4, jit.graph.test4, jit.graph.cgt8, jit.graph.cgt10, jit.graph.cgt7, jit.graph.CGT, jit.graph.cgt6, jit.graph.test6, jit.graph.cgt11, jit.graph.test1, jit.graph.cgt1, jit.graph.Globals, jit.graph.RBTree, jit.graph.cgt0
elapsed time (seconds): 1.024
result: Error. Agent communication error: java.io.EOFException; check console log for any additional details

#section:compile
----------messages:(5/3177)----------
command: compile /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test3.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt3.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/Node.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test2.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt2.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/MethodData.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt9.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt5.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test5.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt4.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test4.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt8.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt10.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt7.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/CGT.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt6.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test6.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt11.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/test1.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt1.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/Globals.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/RBTree.java /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase/jit/graph/cgt0.java
reason: .class file out of date or does not exist
Mode: agentvm
Agent id: 3
elapsed time (seconds): 1.024
----------configuration:(11/1592)----------
Boot Layer (javac runtime environment)
  class path: /System/Volumes/Data/mesos/work_dir/jib-master/install/jtreg/6.1/1/bundles/jtreg-6.1+1.zip/jtreg/lib/javatest.jar
              /System/Volumes/Data/mesos/work_dir/jib-master/install/jtreg/6.1/1/bundles/jtreg-6.1+1.zip/jtreg/lib/jtreg.jar
  patch: java.base /System/Volumes/Data/mesos/work_dir/slaves/a2dc162d-743b-4800-9e92-31f85abb45b1-S162355/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/083c0d94-ab1b-40a7-a1e6-160e542ad0c9/runs/30d59cfc-6a3e-47d0-b474-e4417a313726/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_vm_compiler/patches/java.base

javac compilation environment
  source path: /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/hotspot/jtreg/vmTestbase
               /System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-19+4-126/src.full/open/test/lib
  class path: /System/Volumes/Data/mesos/work_dir/slaves/a2dc162d-743b-4800-9e92-31f85abb45b1-S162355/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/083c0d94-ab1b-40a7-a1e6-160e542ad0c9/runs/30d59cfc-6a3e-47d0-b474-e4417a313726/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_vm_compiler/classes/0/vmTestbase
               /System/Volumes/Data/mesos/work_dir/slaves/a2dc162d-743b-4800-9e92-31f85abb45b1-S162355/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/083c0d94-ab1b-40a7-a1e6-160e542ad0c9/runs/30d59cfc-6a3e-47d0-b474-e4417a313726/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_vm_compiler/classes/0/test/lib

----------rerun:(40/10707)*----------

<snip>

result: Error. Agent communication error: java.io.EOFException; check console log for any additional details


Please note there are no signs of a VM crash:

- no core file
- no hs_err_pid file
- the test task's stdout log shows this failure, but no other
  indication of something that went wrong.
- the test task's stderr log shows no issues

I'm starting this bug in tools/jtreg since

     "Agent communication error: java.io.EOFException"

indicates a problem with jtreg Agent communication.