In a personal CI job, the runtime/jni/codegenAttachThread/TestCodegenAttach.java test failed due to a JVM crash which looked like:

[error occurred during error reporting (), id 0xe0000000, Internal Error (/jdk/src/hotspot/share/runtime/thread.hpp:660)]
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00000001005b0018, pid=66286, tid=27139
#
# JRE version: Java(TM) SE Runtime Environment (26.0) (fastdebug build 26-internal-2025-10-02-1521441.jaikiran.pai.jdk)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 26-internal-2025-10-02-1521441.jaikiran.pai.jdk, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, bsd-aarch64)
# Problematic frame:
# C 0x00000001005b0018
...
Host: macos-aarch64-host, "Mac14,3" arm64, 8 cores, 16G, Darwin 24.6.0, macOS 15.7 (24G222)
Time: Thu Oct 2 16:07:12 2025 GMT elapsed time: 0.099712 seconds (0d 0h 0m 0s)

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

Current thread is native thread

Stack: [0x0000000172138000,0x00000001721bb000], sp=0x00000001721baf90, free space=523k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C 0x00000001005b0018
C [libcodegenAttach.dylib+0x3bfc] thread_start+0x34
C [libsystem_pthread.dylib+0x6bc8] _pthread_start+0x88

siginfo: si_signo: 11 (SIGSEGV), si_code: 2 (SEGV_ACCERR), si_addr: 0x0000000000000000
...

The complete hs_err file is attached to this issue. No specific code changes were involved in this run as compared to the mainline JDK build as of 1st October.

The host was on macOS 15.7 aarch64 (M2).