protected void waitRunning() {
		waitState(1, () -> 0L, TraceExecutionState.RUNNING);
	}
This seems like a bug in gdb. AFAICT, it's a rehash or regression of
https://sourceware.org/bugzilla/show_bug.cgi?id=17247. If I attach to the
hung gdb, I get a similar stack trace, but with Python frames on the
stack. The workaround given in the comments works here, too. I hesitate
to point fingers, though, because I'm testing with a modern gdb-13.1
compiled from source on a rather un-modern distro.
Ghidra/Test/DebuggerIntegrationTest/src/test.slow/java/agent/gdb/rmi/AbstractGdbTraceRmiTest.java