Category
   library
Sub-Category
   libc
Description
   We're seeing a Java hang on Java 1.4.2_11 and similar versions under OpenSolaris that we don't see on Solaris 10; we've seen it in a Java installer on a real app but have managed to find that the test code in the code attached to
 bugs.sun.com bug 4317961:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4317961
also exhibits a similar hang.
  That bug suggests it was fixed years ago in much earlier versions of Java; and as I say it works on Sol 10.
We noticed that during the hang it was often in thr_getstate()
A colleague wondered if the problem might be related to getgregs and noticed it only copies some of the registers; he added copying of other registers and noticed
adding nPC seemed to fix the hang - but it would be nice if we understood why this was the case.
Frequency
   Always
Regression
   Solaris 10
Steps to Reproduce
   Run the code on:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4317961
in java 1.4.2 on SPARC - it hangs. (Note I seems the classname got changed given what it is calling in main on the oriignal bug?)
public class sf {
        static public boolean _xx = true;
public static void main(String[] args) {
new sf().start();
}
public void start() {
new TesterThread().start();
new GCThread().start();
}
class TesterThread extends Thread {
                // trick compiler 2 in believing that this is not and endless loop
                public void loop (int n) {
long counter = 0;
while (_xx) {
if (n == 0) {
                                  _xx = false;
                                }
}
                }
public void run () {
System.out.println("Start loop");
                        loop(3);
}
}
class GCThread extends Thread {
public void run () {
System.out.println("Starting GC loop");
long counter = 0;
while (true) {
  try { sleep(250); } catch (InterruptedException ix) {}
System.gc();
                                counter++;
                                if (counter == 10) {
                                  _xx = false;
                                  return;
                                }
}
}
}
Expected Result
   Start loop
Starting GC loop
a few lines of GC diag and then exit after a few seconds.
Actual Result
   Hangs reliably.
Error Message(s)
   
Test Case
   from: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4317961
public class sf {
        static public boolean _xx = true;
public static void main(String[] args) {
new sf().start();
}
public void start() {
new TesterThread().start();
new GCThread().start();
}
class TesterThread extends Thread {
                // trick compiler 2 in believing that this is not and endless loop
                public void loop (int n) {
long counter = 0;
while (_xx) {
if (n == 0) {
                                  _xx = false;
                                }
}
                }
public void run () {
System.out.println("Start loop");
                        loop(3);
}
}
class GCThread extends Thread {
public void run () {
System.out.println("Starting GC loop");
long counter = 0;
while (true) {
  try { sleep(250); } catch (InterruptedException ix) {}
System.gc();
                                counter++;
                                if (counter == 10) {
                                  _xx = false;
                                  return;
                                }
}
}
}
Workaround
   
Submitter wants to work on bug
   No
Additional configuration information