The following test failed in the JDK26 CI:

applications/jcstress/seqcst.java

Here's a snippet from the log file:

Exception in thread "main" java.lang.AssertionError: TEST FAILURES:
org.openjdk.jcstress.tests.seqcst.volatiles.L1_L1_S1__S1__S2__S2_Test [-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -XX:MaxRAMPercentage=25, -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-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/tmp, -XX:+TieredCompilation, -XX:TieredStopAtLevel=1, -XX:+HeapDumpOnOutOfMemoryError, -XX:+CrashOnOutOfMemoryError]: Observed forbidden state: 3, 3, 3, 4 (No default case provided, assume Forbidden)
org.openjdk.jcstress.tests.seqcst.volatiles.L1_S2_S3__L2_L3__S1_Test [-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -XX:MaxRAMPercentage=25, -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-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/tmp, -XX:+TieredCompilation, -XX:TieredStopAtLevel=1, -XX:+HeapDumpOnOutOfMemoryError, -XX:+CrashOnOutOfMemoryError]: Observed forbidden state: 0, 0, 0, 3, 0, 2 (No default case provided, assume Forbidden)
org.openjdk.jcstress.tests.seqcst.volatiles.L1_S2_S3__L2_L3__S1_Test [-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/scratch, -XX:MaxRAMPercentage=25, -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-S190058/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f2fc350e-421b-49e5-a9cd-307c284375d0/runs/61a1bfbf-33a3-4130-8ab3-5e6eebc419da/testoutput/test-support/jtreg_open_test_hotspot_jtreg_jcstress_part1/tmp, -XX:+TieredCompilation, -XX:TieredStopAtLevel=1, -XX:+HeapDumpOnOutOfMemoryError, -XX:+CrashOnOutOfMemoryError]: Observed forbidden state: 3, 0, 0, 3, 0, 0 (No default case provided, assume Forbidden)

at org.openjdk.jcstress.infra.grading.ExceptionReportPrinter.work(ExceptionReportPrinter.java:63)
at org.openjdk.jcstress.JCStress.parseResults(JCStress.java:162)
at org.openjdk.jcstress.JCStress.run(JCStress.java:85)
at org.openjdk.jcstress.Main.main(Main.java:57)
]cout/cerr
java.lang.Error: jctress test finished with nonzero exitcode 1
at applications.jcstress.JcstressRunner.main(JcstressRunner.java:89)
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.Error
JavaTest Message: shutting down test

result: Failed. Execution failed: `main' threw exception: java.lang.Error: jctress test finished with nonzero exitcode 1

I'm starting this issue off in hotspot/test for initial evaluation.