--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/test/jdk/jdk/jfr/event/io/EvilInstrument.java	2018-04-09 18:09:31.731190685 +0200
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.event.io;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.RandomAccessFile;
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.Instrumentation;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.security.ProtectionDomain;
+import java.util.concurrent.CountDownLatch;
+
+
+/**
+ * @test
+ * @key jfr
+ * @summary This test runs JFR with a javaagent that reads/writes files and
+ * sockets during every class definition. This is to verify that the i/o
+ * instrumentation in JFR does not interfere with javaagents.
+ *
+ * @library /test/lib /test/jdk
+ * @modules java.instrument
+ *
+ * @run shell MakeJAR.sh EvilInstrument 'Can-Redefine-Classes: true'
+ * @run main/othervm -javaagent:EvilInstrument.jar jdk.jfr.event.io.EvilInstrument
+ */
+
+public class EvilInstrument {
+
+    CountDownLatch socketEchoReady = new CountDownLatch(1);
+    ServerSocket ss;
+
+    /**
+     * Thread that echos everything from a socket.
+     */
+    class SocketEcho extends Thread
+    {
+        public SocketEcho() {
+            setDaemon(true);
+        }
+
+        public void run() {
+            try {
+                Socket s = ss.accept();
+                OutputStream os = s.getOutputStream();
+                InputStream is = s.getInputStream();
+                socketEchoReady.countDown();
+                for(;;) {
+                    int b = is.read();
+                    os.write(b);
+                }
+            } catch(Exception ex) {
+                ex.printStackTrace();
+                System.exit(1);
+            }
+        }
+    }
+
+    public static File createScratchFile() throws IOException {
+        return File.createTempFile("EvilTransformer", null, new File(".")).getAbsoluteFile();
+    }
+
+    class EvilTransformer implements ClassFileTransformer {
+        File scratch;
+        Socket s;
+        volatile boolean inited = false;
+
+        public EvilTransformer() throws Exception {
+            scratch = createScratchFile();
+            ss = new ServerSocket(0);
+            new SocketEcho().start();
+            s = new Socket(ss.getInetAddress(), ss.getLocalPort());
+            socketEchoReady.await();
+            inited = true;
+        }
+
+        public byte[] transform(ClassLoader loader, String className,
+                                Class<?> classBeingRedefined,
+                                ProtectionDomain protectionDomain,
+                                byte[] classfileBuffer)
+        {
+            if (!inited) {
+                return null;
+            }
+            // Do i/o operations during every transform call.
+            try {
+                FileOutputStream fos = new FileOutputStream(scratch);
+                fos.write(31);
+                fos.close();
+
+                FileInputStream fis = new FileInputStream(scratch);
+                fis.read();
+                fis.close();
+
+                RandomAccessFile raf = new RandomAccessFile(scratch, "rw");
+                raf.read();
+                raf.write(31);
+                raf.close();
+
+                s.getOutputStream().write(31);
+                s.getInputStream().read();
+
+            } catch(Exception ex) {
+                ex.printStackTrace();
+                System.exit(1);
+            }
+            return null;
+        }
+    }
+
+    public static void premain(String agentArgs, Instrumentation inst) {
+        new EvilInstrument().addTransformer(inst);
+    }
+
+    private void addTransformer(Instrumentation inst) {
+        try {
+            inst.addTransformer(new EvilTransformer());
+        } catch(Exception ex) {
+            ex.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    public static void main(String... args) throws Exception {
+        System.out.println("Hello");
+    }
+
+}