If you fix this bug: please mention me, I spent quite some time extracting the JASM file for you to have a simple reproducer ;)

Affected:
JDK23 - JDK11, maybe further back (did not check more).

Product gives us:
Error: Unable to initialize main class TestClassNew
Caused by: java.lang.LinkageError: Illegal class file encountered. Try running with -Xverify:all in method main

Debug reproduces/asserts immediately.
emanuel@emanuel-oracle:xyz$ java -jar ~/Documents/asmtools-7.0-build/release/lib/asmtools.jar jasm Test.jasm
emanuel@emanuel-oracle:xyz$ /oracle-work/jdk-fork2/build/linux-x64-debug/jdk/bin/java Test

# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/oracle-work/jdk-fork2/open/src/hotspot/share/oops/generateOopMap.cpp:401), pid=3707675, tid=3707676
# assert(bci>= 0 && bci < c->method()->code_size()) failed: index out of bounds
#
# JRE version: Java(TM) SE Runtime Environment (24.0) (fastdebug build 24-internal-2024-06-13-1913126.emanuel...)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 24-internal-2024-06-13-1913126.emanuel..., mixed mode, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0xd5b5c8] GenerateOopMap::bb_mark_fct(GenerateOopMap*, int, int*) [clone .part.0]+0x28
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport -p%p -s%s -c%c -d%d -P%P -u%u -g%g -- %E" (or dumping to /oracle-work/???/files-for-report/24-13/core.3707675)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp

bci = 39, c->method()->code_size() = 39

We are at bci 36, where the jsr bytecode is. Then, we want to step the length of that bytecode forward, i.e. +3, and mark the bci there as a block header. But that is the end of the code, i.e. there is nothing after the jsr.

I extracted a simple JASM test:

super public class Test
{
    public static Method main:"([Ljava/lang/String;)V"
    stack 100 locals 100
    {
        return;
    LABEL:
        nop;
        jsr LABEL; // bci=2. Compute bci + length(jsr) -> bci = 5 accessed, out of bounds.
    }
}