In case of JVM crashes in the build, we print some info about the crash at the end of the build log file In the "Output from failing command(s) repeated here …" section .
Example from a recent crash on AIX :

=== Output from failing command(s) repeated here ===
/opt/freeware/bin/printf "* For target jdk__optimize_image_exec:\n"
* For target jdk__optimize_image_exec:
(/opt/freeware/bin/grep -v -e "^Note: including file:" < /nightly/output-jdk-test/make-support/failure-logs/jdk__optimize_image_exec.log || true) | /opt/freeware/bin/head -n 12
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x3c0009003cc0a080, pid=34341128, tid=258
#
# JRE version: OpenJDK Runtime Environment (14.0.1) (build 14.0.0.1-internal+0-adhoc.openjdk.jdk)
# Java VM: OpenJDK 64-Bit Server VM (14.0.0.1-internal+0-adhoc.openjdk.jdk, mixed mode, tiered, compressed oops, serial gc, aix-ppc64)
# Problematic frame:
# C 0x3c0009003cc0a080
#
# Core dump will be written. Default location: /nightly/jdk/make/core or core.34341128
#

Unfortunately , we miss the path to the hs_error file which is a pity because this is a VERY important info in the error analysis .

The reason seems to be that we currently only print 12 lines (head -n 12) and this is not enought to get the line with the hs_error file.