The following test crashed with SIGBUS in the JDK26 CI:

java/lang/System/i18nEnvArg.java

Here's a snippet from the log file:

#section:main
----------messages:(8/234)----------
command: main i18nEnvArg
reason: User specified action: run main i18nEnvArg
started: Wed Aug 20 14:08:08 UTC 2025
Mode: agentvm
Agent id: 384
Process id: 2560742
finished: Wed Aug 20 14:10:41 UTC 2025
elapsed time (seconds): 153.255
----------configuration:(14/1841)----------

<snip>

----------stdout:(19/1377)----------
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGBUS (0x7) at pc=0x0000ffff9af38ebd, pid=2560742, tid=2561024
#
# JRE version: Java(TM) SE Runtime Environment (26.0+12) (fastdebug build 26-ea+12-1224)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 26-ea+12-1224, compiled mode, tiered, compressed oops, compressed class ptrs, g1 gc, linux-aarch64)
# Problematic frame:
# V [libjvm.so+0x21a7ebd]
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221116/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/bad8c375-25cd-40aa-9b39-64c6fdaef7fc/runs/f1f7434b-a733-4edc-acf4-5c65aa14db4a/testoutput/test-support/jtreg_open_test_jdk_jdk_lang/scratch/6/core.2560742)
#
# An error report file with more information is saved as:
# /opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S221116/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/bad8c375-25cd-40aa-9b39-64c6fdaef7fc/runs/f1f7434b-a733-4edc-acf4-5c65aa14db4a/testoutput/test-support/jtreg_open_test_jdk_jdk_lang/scratch/6/hs_err_pid2560742.log
[58.315s][warning][os] Loading hsdis library failed
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#
result: Error. Agent communication error: java.io.EOFException; check console log for any additional details


Here's the crashing thread's stack:

--------------- T H R E A D ---------------

Current thread (0x0000ffff94742e00): JavaThread "AgentVMThread" [_thread_in_vm, id=2561024, stack(0x0000ffff68656000,0x0000ffff68854000) (2040K)]

Stack: [0x0000ffff68656000,0x0000ffff68854000], sp=0x0000ffff68851190, free space=2028k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x21a7ebd]
[error occurred during error reporting (printing native stack (with source info)), id 0xe0000000, Internal Error (/opt/mach5/mesos/work_dir/slaves/f7f8bd65-a387-4a2b-b519-702f2fefaf87-S165683/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/e8d604f8-4515-4561-9cde-57ef030dc0e6/runs/7f35bf72-c69e-408a-ba14-5d8b6ceb640d/workspace/open/src/hotspot/share/utilities/elfFile.cpp:742)]

Retrying call stack printing without source information...

[error occurred during error reporting (retry printing native stack (no source info)), id 0xb, SIGSEGV (0xb) at pc=0x0000ffff9b06bc8c]
Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
J 5668 java.lang.ClassLoader.findLoadedClass0(Ljava/lang/String;)Ljava/lang/Class; java.base@26-ea (0 bytes) @ 0x0000ffff846223f0 [0x0000ffff84622340+0x00000000000000b0]
J 6556 c2 jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(Ljava/lang/String;Z)Ljava/lang/Class; java.base@26-ea (143 bytes) @ 0x0000ffff846a53f4 [0x0000ffff846a5240+0x00000000000001b4]
j jdk.internal.loader.BuiltinClassLoader.loadClass(Ljava/lang/String;Z)Ljava/lang/Class;+3 java.base@26-ea
j java.lang.ClassLoader.loadClass(Ljava/lang/String;Z)Ljava/lang/Class;+38 java.base@26-ea
J 5661 c2 java.lang.ClassLoader.loadClass(Ljava/lang/String;)Ljava/lang/Class; java.base@26-ea (7 bytes) @ 0x0000ffff84621030 [0x0000ffff84620fc0+0x0000000000000070]
v ~StubRoutines::Stub Generator call_stub_stub 0x0000ffff83b7f4cc
j i18nEnvArg.main([Ljava/lang/String;)V+144
J 5379 c1 java.lang.invoke.LambdaForm$DMH+0x000000000e081800.invokeStatic(Ljava/lang/Object;Ljava/lang/Object;)V java.base@26-ea (14 bytes) @ 0x0000ffff7d802f8c [0x0000ffff7d802900+0x000000000000068c]
J 11246 c1 java.lang.invoke.LambdaForm$MH+0x000000000e08d000.invoke(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; java.base@26-ea (38 bytes) @ 0x0000ffff7ed4f80c [0x0000ffff7ed4ee00+0x0000000000000a0c]
J 11253 c1 java.lang.invoke.Invokers$Holder.invokeExact_MT(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; java.base@26-ea (24 bytes) @ 0x0000ffff7ed606d4 [0x0000ffff7ed5f980+0x0000000000000d54]
j jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;+55 java.base@26-ea
j jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;+23 java.base@26-ea
J 11079 c1 com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run()V (170 bytes) @ 0x0000ffff7ec828c4 [0x0000ffff7ec81700+0x00000000000011c4]
J 3988 c2 java.lang.Thread.run()V java.base@26-ea (23 bytes) @ 0x0000ffff84533c60 [0x0000ffff84533b80+0x00000000000000e0]
v ~StubRoutines::Stub Generator call_stub_stub 0x0000ffff83b7f4cc

siginfo: si_signo: 7 (SIGBUS), si_code: 1 (BUS_ADRALN), si_addr: 0x0000ffff9af38ebd

I'm starting this bug off in hotspot/runtime since most of
the code on the stack is class loader related...