From 17b4db31cbc5c2b4829c2d38b832832b874ae28e Mon Sep 17 00:00:00 2001
From: Maurizio Cimadamore <mcimadamore@openjdk.org>
Date: Tue, 12 Jan 2021 21:06:03 +0000
Subject: [PATCH] 8259636: Check for buffer backed by shared segment kicks in
 in unexpected places

Reviewed-by: sundar, alanb, chegar
---
 .../classes/java/nio/Direct-X-Buffer.java.template     |  2 +-
 test/jdk/java/foreign/TestByteBuffer.java              | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template b/src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
index f3e1c8b2248..5257c1e2e59 100644
--- a/src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
+++ b/src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
@@ -203,7 +203,7 @@ class Direct$Type$Buffer$RW$$BO$
     {
 #if[rw]
         super(mark, pos, lim, cap, segment);
-        address = db.address() + off;
+        address = ((Buffer)db).address + off;
 #if[byte]
         cleaner = null;
 #end[byte]
diff --git a/test/jdk/java/foreign/TestByteBuffer.java b/test/jdk/java/foreign/TestByteBuffer.java
index 27d7a8a3e00..d5b9b5a040f 100644
--- a/test/jdk/java/foreign/TestByteBuffer.java
+++ b/test/jdk/java/foreign/TestByteBuffer.java
@@ -64,7 +64,6 @@
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.function.BiConsumer;
@@ -668,6 +667,15 @@ public void buffersAndArraysFromSlices(Supplier<MemorySegment> segmentSupplier)
         }
     }
 
+    @Test(dataProvider="segments")
+    public void viewsFromSharedSegment(Supplier<MemorySegment> segmentSupplier) {
+        try (MemorySegment segment = segmentSupplier.get().share()) {
+            var byteBuffer = segment.asByteBuffer();
+            byteBuffer.asReadOnlyBuffer();
+            byteBuffer.slice(0, 8);
+        }
+    }
+
     @DataProvider(name = "segments")
     public static Object[][] segments() throws Throwable {
         return new Object[][] {