I've seen a variety of crashes and a couple deadlocks running the JMH from the http://hg.openjdk.java.net/code-tools/jmh-jdk-microbenchmarks/ project:

/opt/jdk-11-b9/bin/java -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+TieredCompilation -XX:+UseJVMCICompiler -Djvmci.compiler=graal -jar target/jmh-jdk-microbenchmarks-1.0-SNAPSHOT.jar bulk_par_lambda -t 1 -rf json -rff jmh.json -wi 1 -i 1

Doesn't seem to happen with +UseParallelGC.
Trying older builds, problems happen at least as early as 11-b3.