The jvm crashed on the ThreadGCBug test when the recent symantec jit is turned on. The crashed happened normally in one second.

Some visible phenomena includes the corrupted heap, weak reference error,
fatal page fault and dead lock.

The following is the test source code. Just compile it and run with
java -Djava.compiler=symcjit ThreadGCBug

class T implements Runnable {
  static int nInstance = 0;
  synchronized public static int getNInstance() {return nInstance;}
  synchronized public static int incNInstance() {return nInstance++;}
  synchronized public static int decNInstance() {return nInstance--;}
  
  public void run2(String a[], String a1[], int sz, String sum) {
      int i;
      for(i=0;i<sz;i++)
        a1[i] = null;
      int s = 0;
      int inc;
      String b;
      for (i=0;i<sz;i++) {
        inc = a[i].length();
if (!a[i].regionMatches(0, sum, s, inc)) {
          System.out.print ("failed: i = " + i + "\n");
          System.out.print (" a[i] = " + a[i] + "\n");
          b = sum.substring(s, s+inc);
          System.out.print (" b = " + b + "\n");
int j;
for (j=0;j<inc;j++)
System.out.print ((int)(a[i].charAt(j)) + " " + (int)(b.charAt(j)) + "\n");
          break;
        }
        s += inc;
      }
  }

  public void run1(int pass) {
      int i;
      int res;
      int sz = 121;
      String[] a = new String [sz];
      String[] a1 = new String [sz];
      String sum = "1";

      a[0] = "1";
      for (i=1;i<sz;i++) {
        a[i] = a[i-1] + i;
        a1[i] = sum;
        sum = sum + a[i];
      }
      run2(a,a1,sz,sum);
      System.out.print (Thread.currentThread() + ": pass " + pass + "\n");
  }
  public void run() {
      try {
      int i;
      int n = (int)(10.0 * Math.random());
      for(i=0;i<n;i++)
        run1(i);
      decNInstance();
} catch (Throwable t) {
t.printStackTrace();
}
  }
}


class HT implements Runnable {

  public void run() {
      while(true) {
try {
          Thread.sleep(50);
        } catch (Exception e) {
e.printStackTrace();
}
      }
  }
}

class ThreadGCBug {
  public static void main1 (String[] args) {
    Thread ht = new Thread(new HT());
    ht.setPriority(7);
    ht.start();
    while (true) {
      T.incNInstance();
      Thread t = new Thread(new T());
      t.start();
      while (T.getNInstance() > 2) {
        try {Thread.sleep(100);}
catch (Exception e) {
e.printStackTrace();
}
      }
    }
  }
  public static void main (String[] args) {
    main1(args);
    int i;
    for (i=0;i<10000;i++) {
      int a[] = new int [100];
      a [9] = i;
    }
try{Thread.sleep(100000);} catch (Throwable e) {}
  }
}