This is a test that was recently modified to expect OpaqueFrameException from JDI, since it uses underlying debugging functionality that is not supported for vthreads (setting a local on a frame that is not the topmost frame). Changing it to expect OpaqueFrameException allows the test to pass, and it was also removed from the problem list at the time:

https://github.com/openjdk/loom/commit/6a9145b68e691853c7eeddb6409409137cde7b7b

This is the failure:

setValue(variable, null)
# ERROR: debugger FAILURE> Expected OpaqueFrameException
The following stacktrace is for failure analysis.
nsk.share.TestFailure: debugger FAILURE> Expected OpaqueFrameException
at nsk.share.Log.logExceptionForFailureAnalysis(Log.java:432)
at nsk.share.Log.complain(Log.java:403)
at nsk.jdi.StackFrame._bounds_.bounds002.complain(bounds002.java:68)
at nsk.jdi.StackFrame._bounds_.bounds002.execTest(bounds002.java:192)
at nsk.jdi.StackFrame._bounds_.bounds002.run(bounds002.java:86)
at nsk.jdi.StackFrame._bounds_.bounds002.main(bounds002.java:72)

The reason this is expected to result in OpaqueFrameException is because StackFrame.setValue() is called on the debuggee main() method, and the debuggee is expected to be blocked on the pipe.readln() call that is made from main(), thus main() is expected to not be the topmost frame. However, it's possible that after initially suspending the debuggee, main() has not yet made it as far as the pipe.readln() call, so it is actually safe to set a local in the main() method.

There is a loop at the top of the test that looks for main() in the stack trace. It should also be able to determine if main() is the topmost frame or not, and then adjust the test's expectations based on that.