Async Profiler (https://github.com/jvm-profiling-tools/async-profiler) is able to generate JFR recordings with CPU and allocation sample events spanning full-stack (from Java to OS/kernel).
It is adding 3 new frame types for this reason:

• Native (C)
• C++
• Kernel

Currently, the JMC parser will process all those frame types as 'UNKNOWN'. Although it is not breaking the rendering it would be nice to be able to get more info about the actual frame type.