The following test failed in the Valhalla CI:

serviceability/sa/TestJhsdbJstackMixedWithXComp.java#xcomp

Here's a snippet from the log file:

#section:driver
----------messages:(8/282)----------
command: driver TestJhsdbJstackMixedWithXComp
reason: User specified action: run driver TestJhsdbJstackMixedWithXComp
started: Sat Jan 03 08:57:58.467 UTC 2026
Mode: agentvm
Agent id: 60
Process id: 1927969
finished: Sat Jan 03 08:59:16.844 UTC 2026
elapsed time (seconds): 78.377
----------configuration:(14/1995)----------

<snip>

----------System.out:(413/28253)----------
Command line: ['/opt/mach5/mesos/work_dir/jib-master/install/jdk-27-valhalla+1-16/linux-x64-debug.jdk/jdk-27/fastdebug/bin/java' '-XX:MaxRAMPercentage=4.16667' '-Dtest.boot.jdk=/opt/mach5/mesos/work_dir/jib-master/install/jdk/25/37/bundles/linux-x64/jdk-25_linux-x64_bin.tar.gz/jdk-25' '-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/da1065b5-7b94-4f0d-85e9-a3a252b9a32e-S28326/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/ca95aecc-3141-432a-9c68-8b424e190cd3/runs/16aabdbf-8c65-4520-84cd-3dcf8925d817/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_serviceability/tmp' '-Xcomp' '-ea' '-esa' '-XX:CompileThreshold=100' '-XX:+UnlockExperimentalVMOptions' '-server' '-XX:+TieredCompilation' '-XX:+DeoptimizeALot' '-Xcomp' '-cp' '/opt/mach5/mesos/work_dir/slaves/da1065b5-7b94-4f0d-85e9-a3a252b9a32e-S28326/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/ca95aecc-3141-432a-9c68-8b424e190cd3/runs/16aabdbf-8c65-4520-84cd-3dcf8925d817/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_serviceability/classes/4/serviceability/sa/TestJhsdbJstackMixedWithXComp_xcomp.d:/opt/mach5/mesos/work_dir/slaves/da1065b5-7b94-4f0d-85e9-a3a252b9a32e-S28326/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/ca95aecc-3141-432a-9c68-8b424e190cd3/runs/16aabdbf-8c65-4520-84cd-3dcf8925d817/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_serviceability/classes/4/serviceability/sa/TestJhsdbJstackMixedWithXComp_xcomp.d/test/lib' 'LingeredAppWithVirtualThread' '46f9981f-6cf0-4b20-a792-7eefc4f33ced.lck']
LingeredApp startup took 32108ms
Check for hs_err_pid/core/mdmp files:
None.
Started LingeredApp with pid 1928002
[2026-01-03T08:58:31.541586336Z] Gathering output for process 1928435
Attaching to process ID 1928002, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 27-valhalla+1-16
Deadlock Detection:

can't print deadlock information: sun.jvm.hotspot.runtime.ConstructionException: java.lang.NullPointerException: Cannot invoke "java.lang.Class.getConstructor(java.lang.Class[])" because "clazz" is null
----------------- 1928432 -----------------

<snip>

----------System.err:(447/29157)----------
java.lang.NullPointerException: Cannot invoke "sun.jvm.hotspot.debugger.linux.amd64.DwarfParser.getBasePointerOffsetFromCFA()" because "nextDwarf" is null
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.linux.amd64.LinuxAMD64CFrame.getNextCFA(LinuxAMD64CFrame.java:133)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.linux.amd64.LinuxAMD64CFrame.sender(LinuxAMD64CFrame.java:207)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.PStack.run(PStack.java:195)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.PStack.run(PStack.java:65)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.PStack.run(PStack.java:60)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.JStack.run(JStack.java:67)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:278)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.start(Tool.java:241)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.execute(Tool.java:134)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.JStack.runWithArgs(JStack.java:90)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runJSTACK(SALauncher.java:306)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:507)

 stdout: [Attaching to process ID 1928002, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 27-valhalla+1-16
Deadlock Detection:

can't print deadlock information: sun.jvm.hotspot.runtime.ConstructionException: java.lang.NullPointerException: Cannot invoke "java.lang.Class.getConstructor(java.lang.Class[])" because "clazz" is null
----------------- 1928432 -----------------


This line occurs first in the stderr section, but not in the stdout section:

java.lang.NullPointerException: Cannot invoke "sun.jvm.hotspot.debugger.linux.amd64.DwarfParser.getBasePointerOffsetFromCFA()" because "nextDwarf" is null

and this line appears second in stderr section:

can't print deadlock information: sun.jvm.hotspot.runtime.ConstructionException: java.lang.NullPointerException: Cannot invoke "java.lang.Class.getConstructor(java.lang.Class[])" because "clazz" is null

I went with the nextDwarf error in this issue's synopsis since I think it is the first error.