8240521: Revert backport of 8231584: Deadlock with ClassLoader.findLibrary and...

8240521: Revert backport of 8231584: Deadlock with ClassLoader.findLibrary and System.loadLibrary call
Reviewed-by: andrew

src/share/classes/java/lang/ClassLoader.java

 /*
  * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Azul Systems, Inc. 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
@@ -1468,17 +1467,6 @@ public abstract class ClassLoader {
         }
     }
 
-    /*
-     * Initialize default paths for native libraries search.
-     * Must be done early as JDK may load libraries during bootstrap.
-     *
-     * @see java.lang.System#initPhase1
-     */
-    static void initLibraryPaths() {
-        usr_paths = initializePath("java.library.path");
-        sys_paths = initializePath("sun.boot.library.path");
-    }
-
     // Returns true if the specified class loader can be found in this class
     // loader's delegation chain.
     boolean isAncestor(ClassLoader cl) {
@@ -1821,9 +1809,10 @@ public abstract class ClassLoader {
                             boolean isAbsolute) {
         ClassLoader loader =
             (fromClass == null) ? null : fromClass.getClassLoader();
-        assert sys_paths != null : "should be initialized at this point";
-        assert usr_paths != null : "should be initialized at this point";
-
+        if (sys_paths == null) {
+            usr_paths = initializePath("java.library.path");
+            sys_paths = initializePath("sun.boot.library.path");
+        }
         if (isAbsolute) {
             if (loadLibrary0(fromClass, new File(name))) {
                 return;
@@ -1913,14 +1902,13 @@ public abstract class ClassLoader {
                          name +
                          " already loaded in another classloader");
                 }
-                /*
-                 * When a library is being loaded, JNI_OnLoad function can cause
-                 * another loadLibrary invocation that should succeed.
+                /* If the library is being loaded (must be by the same thread,
+                 * because Runtime.load and Runtime.loadLibrary are
+                 * synchronous). The reason is can occur is that the JNI_OnLoad
+                 * function can cause another loadLibrary invocation.
                  *
-                 * We use a static stack to hold the list of libraries we are
-                 * loading because this can happen only when called by the
-                 * same thread because Runtime.load and Runtime.loadLibrary
-                 * are synchronous.
+                 * Thus we can use a static stack to hold the list of libraries
+                 * we are loading.
                  *
                  * If there is a pending load operation for the library, we
                  * immediately return success; otherwise, we raise

src/share/classes/java/lang/Runtime.java

 /*
  * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Azul Systems, Inc. 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
@@ -798,7 +797,7 @@ public class Runtime {
         load0(Reflection.getCallerClass(), filename);
     }
 
-    void load0(Class<?> fromClass, String filename) {
+    synchronized void load0(Class<?> fromClass, String filename) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkLink(filename);
@@ -859,14 +858,14 @@ public class Runtime {
         loadLibrary0(Reflection.getCallerClass(), libname);
     }
 
-    void loadLibrary0(Class<?> fromClass, String libname) {
+    synchronized void loadLibrary0(Class<?> fromClass, String libname) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkLink(libname);
         }
         if (libname.indexOf((int)File.separatorChar) != -1) {
             throw new UnsatisfiedLinkError(
-                "Directory separator should not appear in library name: " + libname);
+    "Directory separator should not appear in library name: " + libname);
         }
         ClassLoader.loadLibrary(fromClass, libname, false);
     }

src/share/classes/java/lang/System.java

@@ -1195,8 +1195,6 @@ public final class System {
         setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
         setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
 
-        ClassLoader.initLibraryPaths();
-
         // Load the zip library now in order to keep java.util.zip.ZipFile
         // from trying to use itself to load this library later.
         loadLibrary("zip");

test/java/lang/Runtime/loadLibrary/LoadLibraryTest.java

-/*
- * Copyright (c) 2018, Amazon and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Azul Systems, Inc. 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.
- *
- * 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.
- */
-
-/**
- * @test
- * @bug 8231584
- * @library /lib/testlibrary
- * @run main/othervm LoadLibraryTest
- */
-
-import java.nio.file.FileSystems;
-import java.nio.file.Files;
-import java.nio.file.Paths;
-import java.nio.file.Path;
-import java.net.MalformedURLException;
-import java.net.URLClassLoader;
-import java.net.URL;
-
-public class LoadLibraryTest {
-    static Thread thread1 = null;
-    static Thread thread2 = null;
-
-    static volatile boolean thread1Ready = false;
-
-    private static final String TEST_SRC = System.getProperty("test.src");
-    private static final Path SRC_DIR = Paths.get(TEST_SRC, "src");
-    private static final Path CLS_DIR = Paths.get("classes");
-
-    static TestClassLoader loader;
-    static void someLibLoad() {
-        try {
-/*
-            FileSystems.getDefault();
-
-            // jdk/jdk: loads directly from Bootstrap Classloader (doesn't take lock on Runtime)
-            java.net.NetworkInterface.getNetworkInterfaces();
-
-            System.out.println(jdk.net.ExtendedSocketOptions.SO_FLOW_SLA);
-*/
-            Class c = Class.forName("Target2", true, loader);
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    static class TestClassLoader extends URLClassLoader {
-        boolean passed = false;
-
-        public boolean passed() {
-            return passed;
-        }
-
-        TestClassLoader() throws MalformedURLException {
-            super(new URL[] { new URL("file://" + CLS_DIR.toAbsolutePath().toString() + '/') });
-        }
-
-        public String findLibrary(String name) {
-            System.out.println("findLibrary " + name);
-
-            if ("someLibrary".equals(name)) {
-                try {
-                    synchronized(thread1) {
-                        while(!thread1Ready) {
-                            thread1.wait();
-                        }
-                        thread1.notifyAll();
-                    }
-
-                    Thread.sleep(10000);
-
-                    System.out.println("Thread2 load");
-                    someLibLoad();
-
-                    // no deadlock happened
-                    passed = true;
-                } catch (Exception e) {
-                    throw new RuntimeException(e);
-                }
-                return null;
-            }
-
-            return super.findLibrary(name);
-        }
-    }
-
-
-    public static void main(String[] args) throws Exception {
-        loader = new TestClassLoader();
-
-        if (!CompilerUtils.compile(SRC_DIR, CLS_DIR)) {
-            throw new Exception("Can't compile");
-        }
-
-        thread1 = new Thread() {
-            public void run() {
-                try {
-                    synchronized(this) {
-                        thread1Ready = true;
-                        thread1.notifyAll();
-                        thread1.wait();
-                    }
-                } catch(InterruptedException e) {
-                    throw new RuntimeException(e);
-                }
-
-                System.out.println("Thread1 load");
-                someLibLoad();
-            };
-        };
-
-        thread2 = new Thread() {
-            public void run() {
-                try {
-                    Class c = Class.forName("Target", true, loader);
-                    System.out.println(c);
-                } catch (Exception e) {
-                    throw new RuntimeException(e);
-                }
-            };
-        };
-
-        thread1.setDaemon(true);
-        thread2.setDaemon(true);
-
-        thread1.start();
-        thread2.start();
-
-        thread1.join();
-        thread2.join();
-
-        if (!loader.passed()) {
-            throw new RuntimeException("FAIL");
-        }
-    }
-}

test/java/lang/Runtime/loadLibrary/src/Target.java

-/*
- * Copyright (c) 2019, Azul Systems, Inc. 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.
- *
- * 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.
- */
-
-class Target {
-    static {
-        try {
-            System.loadLibrary("someLibrary");
-            throw new RuntimeException("someLibrary was loaded");
-        } catch (UnsatisfiedLinkError e) {
-            // expected: we do not have a someLibrary
-        }
-    }
-}
-

test/java/lang/Runtime/loadLibrary/src/Target2.java

-/*
- * Copyright (c) 2019, Azul Systems, Inc. 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.
- *
- * 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.
- */
-
-class Target2 {
-    static {
-        System.loadLibrary("awt");
-    }
-}
-