Java 17 bug (?) on Windows with MemorySegment.asSlice and offset = 3705032704

[erel at eth.gl]

Hi,

It doesn’t happen on Linux. I’ve tested it with Oracle Java 17.0.3.1 and OpenJDK 17.0.2.

 

Code:

package test.test;

 

import java.io.RandomAccessFile;

import java.nio.channels.FileChannel.MapMode;

import java.nio.file.Path;

 

import jdk.incubator.foreign.MemorySegment;

import jdk.incubator.foreign.ResourceScope;

 

public class Test {

 

      public static void main(String[] args) throws Exception {

            System.out.println(System.getProperty("sun.arch.data.model"));

            System.out.println(System.getProperty("os.arch"));

            System.out.println(System.getProperty("java.version"));

            Path p = Path.of("test.dat");

            RandomAccessFile raf = new RandomAccessFile("test.dat", "rw");

            raf.setLength(8000000000L); //~8gb

            raf.close();

            MemorySegment mappedMemorySegment = MemorySegment.mapFile(p, 0, p.toFile().length(), MapMode.READ_WRITE, ResourceScope.newSharedScope());

            System.out.println("byteSize: " + mappedMemorySegment.byteSize());

            long offset = 3705032702L;

            while (true) {

                  System.out.println("offset: " + offset);

                  MemorySegment target = mappedMemorySegment.asSlice(offset, 1);

                  offset = offset + 1;

                  try {

                        target.force();

                  } catch (Exception e) {

                        e.printStackTrace();

                        return;

                  }

            }

      }

}

 

Output:

WARNING: Using incubator modules: jdk.incubator.foreign

64

amd64

17.0.3.1

byteSize: 8000000000

offset: 3705032702

offset: 3705032703

offset: 3705032704

java.io.UncheckedIOException: java.io.IOException: Attempt to access invalid address

       at java.base/java.nio.MappedMemoryUtils.force(MappedMemoryUtils.java:102)

       at java.base/java.nio.Buffer$1.force(Buffer.java:839)

       at java.base/jdk.internal.misc.ScopedMemoryAccess.forceInternal(ScopedMemoryAccess.java:337)

       at java.base/jdk.internal.misc.ScopedMemoryAccess.force(ScopedMemoryAccess.java:325)

       at jdk.incubator.foreign/jdk.internal.foreign.MappedMemorySegmentImpl.force(MappedMemorySegmentImpl.java:104)

       at test.test.Test.main(Test.java:30)

Caused by: java.io.IOException: Attempt to access invalid address

       at java.base/java.nio.MappedMemoryUtils.force0(Native Method)

       at java.base/java.nio.MappedMemoryUtils.force(MappedMemoryUtils.java:100)

       ... 5 more

 

This is a blocking issue for us. Suggestions will be welcomed.

 

Thanks,

Erel