The following test failed in the JDK26 CI:

runtime/cds/appcds/TestEpsilonGCWithCDS.java#id1

Here's a snippet from the log file:

#section:driver
----------messages:(8/267)----------
command: driver TestEpsilonGCWithCDS false
reason: User specified action: run driver TestEpsilonGCWithCDS false
started: Sat Aug 09 12:14:34 UTC 2025
Mode: agentvm
Agent id: 15
Process id: 198272
finished: Sat Aug 09 12:14:44 UTC 2025
elapsed time (seconds): 10.751
----------configuration:(15/2296)----------

<snip>

1. Exec with -XX:+UseEpsilonGC
Command line: [/opt/mach5/mesos/work_dir/jib-master/install/jdk-26+11-1087/linux-aarch64-debug.jdk/jdk-26/fastdebug/bin/java -cp /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/classes/4/runtime/cds/appcds/TestEpsilonGCWithCDS_id1.d:/opt/mach5/mesos/work_dir/jib-master/install/jdk-26+11-1087/src.full/open/test/hotspot/jtreg/runtime/cds/appcds:/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/classes/4/test/lib:/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/classes/4/test/hotspot/jtreg/runtime/cds/appcds:/opt/mach5/mesos/work_dir/jib-master/install/jtreg/7.5.2/1/bundles/jtreg-7.5.2+1.zip/jtreg/lib/jtreg.jar:/opt/mach5/mesos/work_dir/jib-master/install/jtreg/7.5.2/1/bundles/jtreg-7.5.2+1.zip/jtreg/lib/junit-platform-console-standalone-1.11.0.jar:/opt/mach5/mesos/work_dir/jib-master/install/jtreg/7.5.2/1/bundles/jtreg-7.5.2+1.zip/jtreg/lib/testng-7.3.0.jar:/opt/mach5/mesos/work_dir/jib-master/install/jtreg/7.5.2/1/bundles/jtreg-7.5.2+1.zip/jtreg/lib/jcommander-1.82.jar:/opt/mach5/mesos/work_dir/jib-master/install/jtreg/7.5.2/1/bundles/jtreg-7.5.2+1.zip/jtreg/lib/guice-5.1.0.jar -XX:MaxRAMPercentage=3.125 -Dtest.boot.jdk=/opt/mach5/mesos/work_dir/jib-master/install/jdk/24/36/bundles/linux-aarch64/jdk-24_linux-aarch64_bin.tar.gz/jdk-24 -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/tmp -Xcomp -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation -Xshare:on -showversion -XX:SharedArchiveFile=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/scratch/3/appcds-12h14m34s133.jsa -Dtest.timeout.factor=10.0 -cp /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/scratch/3/hello.jar -XX:+UnlockDiagnosticVMOptions -XX:VerifyArchivedFields=1 -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -showversion -showversion -XX:-UseCompressedOops -Xlog:cds Hello ]
[2025-08-09T12:14:37.886546734Z] Gathering output for process 209180
[ELAPSED: 6892 ms]
[logging stdout to /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/scratch/3/runtime.cds.appcds.TestEpsilonGCWithCDS.java#id1-0001-exec.stdout]
[logging stderr to /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221234/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/76170615-8f55-4249-b1c9-ab7b7cd609e1/runs/30d0b909-dc09-46d3-a07a-0f498493f597/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_tier2_runtime/scratch/3/runtime.cds.appcds.TestEpsilonGCWithCDS.java#id1-0001-exec.stderr]
[STDERR]

[2025-08-09T12:14:44.779110320Z] Waiting for completion for process 209180
[2025-08-09T12:14:44.779223460Z] Waiting for completion finished for process 209180
----------System.err:(16/886)----------
java.lang.RuntimeException: Hotspot crashed
at jdk.test.lib.cds.CDSTestUtils.executeAndLog(CDSTestUtils.java:703)
at jdk.test.lib.cds.CDSTestUtils.executeAndLog(CDSTestUtils.java:679)
at TestCommon.runWithArchive(TestCommon.java:454)
at TestCommon.exec(TestCommon.java:488)
at TestEpsilonGCWithCDS.test(TestEpsilonGCWithCDS.java:115)
at TestEpsilonGCWithCDS.test(TestEpsilonGCWithCDS.java:90)
at TestEpsilonGCWithCDS.main(TestEpsilonGCWithCDS.java:76)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:335)
at java.base/java.lang.Thread.run(Thread.java:1474)

JavaTest Message: Test threw exception: java.lang.RuntimeException
JavaTest Message: shutting down test

result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: Hotspot crashed

Since this test failure is related to EpsilonGC, I'm starting this issue
off in hotspot/gc for initial triage.