Name: mc57594 Date: 12/16/99


The following test case shows the Solaris/x86 JDK 1.2.2 getting
a core dump, rather than the proper StackOverflowException, when the
JIT is on.

The problem is in source file src/share/native/java/io/io_util.c.
Local arrays of BUF_SIZE are allocated in readBytes() and writeBytes().
BUF_SIZE is currently set to 8192. But the JIT's stack overflow
test relies upon no stack frame extending the stack for more than 4096
bytes past its current point (see the "RedZoneSlop" amount and related
comments and logic).

We believe the best solution is to reduce BUF_SIZE to 3072. We don't
think that will degrade I/O performance in any material way, but are
interested in hearing if Sun thinks otherwise.


$ uname -a
SunOS king 5.6 Generic_105182-03 i86pc i386 i86pc

$ $j122b/bin/java -version
java version "1.2.2"
Classic VM (build JDK-1.2.2-001, green threads, sunwjit)

$ cat stack.java
class S extends Thread {
        public int count;
        public long recurse() {
                long l0 = 0;
                long l1 = 1;
                long l2 = 2;
                long l3 = 3;
                long l4 = 4;
                long l5 = 5;
                long l6 = 6;
                long l7 = 7;
                long l8 = 8;
                long l9 = 9;
                count++;
                System.out.println("in recurse count " + count);
                return l0 + l1 + l2 + l3 + l4 + l5 + l6 + l7 + l8 +l9 + recurse();
        }
        public void run() {
                System.out.println("Running in thread " + this);
                recurse();
                System.out.println("Finishing in thread " + this);
        }
}

public class stack {
        public static void main(String[] args) {
                new S().start();
        }
}

$ $j122b/bin/java stack
Running in thread Thread[Thread-0,5,main]
in recurse count 1
in recurse count 2
in recurse count 3
[...]
in recurse count 920
in recurse count 921
Segmentation Fault(coredump)
(Review ID: 98935)
======================================================================