Please see testcase below.

Start it with:
$ /java/jdk1.9.0/bin/java -Xbatch -XX:-BackgroundCompilation -XX:+PrintCompilation -XX:CompileCommand=compileonly,TestBug::test -XX:-UseOnStackReplacement TestBug

It hangs once test method was compiled.
----> Iteration #125, count = 127043862
----> Iteration #126, count = 128052649
  13439 1 b 3 TestBug::test (47 bytes)
----> Iteration #127, count = 129157852
  13544 2 % b 4 TestBug::test @ 31 (47 bytes)
  13545 3 b 4 TestBug::test (47 bytes)
  13548 1 3 TestBug::test (47 bytes) made not entrant

Testcase:
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.lang.ref.Reference;

public class TestBug {
    private static long test() throws Exception {
        long count = 0;
        ReferenceQueue<Object> q = new ReferenceQueue<Object>();

        {
            Object obj = new Object();
            WeakReference<Object> ref = new WeakReference<Object>(obj, q);
            obj = null;
        }

        while (q.poll() == null) {
            count++;
        }

        return count;
    }

    public static void main(String[] args) throws Exception {
        new Thread() {
            public void run() {
                while (true) {
                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                    }

                    System.gc();
                }
            }
        }.start();

        long count = 0;

        for (int i = 0; i < 400; i++) {
            count += test();
            System.out.println("----> Iteration #" + i + ", count = " + count);
        }

        System.out.println(count);
    }
}