while(true){}; causes intermittent hangs

[Vivek Garg]

Hello,

I am using version 0.1.4 of the library and seeing intermittent hangs when using while(true){}; as the input javascript. Here is a test case that reproduces the problem:

  @Test
  public void testIsMatchCpuAbuseDirect() {
    String js = "while (true) {};";
    for (int i = 0; i < 1000; i++) {
      System.out.println("i = " + i);
      NashornSandbox sandbox = NashornSandboxes.create();
      sandbox.setMaxCPUTime(100); // in millis
      sandbox.setMaxMemory(1000 * 1000); // 1 MB
      sandbox.allowNoBraces(false);
      sandbox.setMaxPerparedStatements(30); // because preparing scripts for execution is expensive
      sandbox.setExecutor(Executors.newSingleThreadExecutor());
      Exception exp = null;
      try {
        Object result = sandbox.eval(js);
      } catch (Exception e) {
        exp = e;
      }
      Assert.assertNotNull(exp);
    }
  }

Also worth noting that the test case completes with successfully if the script is changed to: var o={}, i=0; while (true) {o[i++]='a';};

Would appreciate any help on the issue.

[Max Rohde]

Thank you for reporting this issue. There was a bug in the CPU monitor class. This is fixed now and included in version 0.1.6 which should be available in Maven central presently.

Does this solve your issue?

[Vivek Garg]

Thanks @mxro for the quick turnaround on this. I will give this a try Today and report back.

[Vivek Garg]

The fix worked. Thanks Much!!!

[Max Rohde]

Thank you for testing it! I will close the issue now!