8231584: Deadlock with ClassLoader.findLibrary and System.loadLibrary call
Reviewed-by: mchung
--- a/src/java.base/share/classes/java/lang/ClassLoader.java Fri Oct 11 13:14:00 2019 -0700
+++ b/src/java.base/share/classes/java/lang/ClassLoader.java Fri Oct 11 14:49:05 2019 -0700
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2013, 2019, 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
@@ -2004,6 +2005,17 @@
return scl;
}
+ /*
+ * 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) {
@@ -2473,8 +2485,7 @@
*
* 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.
+ * same thread because this block is synchronous.
*
* If there is a pending load operation for the library, we
* immediately return success; otherwise, we raise
@@ -2619,10 +2630,9 @@
boolean isAbsolute) {
ClassLoader loader =
(fromClass == null) ? null : fromClass.getClassLoader();
- if (sys_paths == null) {
- usr_paths = initializePath("java.library.path");
- sys_paths = initializePath("sun.boot.library.path");
- }
+ assert sys_paths != null : "should be initialized at this point";
+ assert usr_paths != null : "should be initialized at this point";
+
if (isAbsolute) {
if (loadLibrary0(fromClass, new File(name))) {
return;
--- a/src/java.base/share/classes/java/lang/Runtime.java Fri Oct 11 13:14:00 2019 -0700
+++ b/src/java.base/share/classes/java/lang/Runtime.java Fri Oct 11 14:49:05 2019 -0700
@@ -1,5 +1,6 @@
/*
* Copyright (c) 1995, 2019, 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
@@ -732,7 +733,7 @@
load0(Reflection.getCallerClass(), filename);
}
- synchronized void load0(Class<?> fromClass, String filename) {
+ void load0(Class<?> fromClass, String filename) {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkLink(filename);
@@ -794,14 +795,14 @@
loadLibrary0(Reflection.getCallerClass(), libname);
}
- synchronized void loadLibrary0(Class<?> fromClass, String libname) {
+ 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);
}
--- a/src/java.base/share/classes/java/lang/System.java Fri Oct 11 13:14:00 2019 -0700
+++ b/src/java.base/share/classes/java/lang/System.java Fri Oct 11 14:49:05 2019 -0700
@@ -2045,6 +2045,8 @@
// register shared secrets
setJavaLangAccess();
+ ClassLoader.initLibraryPaths();
+
// Subsystems that are invoked during initialization can invoke
// VM.isBooted() in order to avoid doing things that should
// wait until the VM is fully initialized. The initialization level
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/Runtime/loadLibrary/LoadLibraryTest.java Fri Oct 11 14:49:05 2019 -0700
@@ -0,0 +1,158 @@
+/*
+ * 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 /test/lib
+ * @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;
+
+import jdk.test.lib.compiler.CompilerUtils;
+
+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");
+ }
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/Runtime/loadLibrary/src/Target.java Fri Oct 11 14:49:05 2019 -0700
@@ -0,0 +1,34 @@
+/*
+ * 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
+ }
+ }
+}
+
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/Runtime/loadLibrary/src/Target2.java Fri Oct 11 14:49:05 2019 -0700
@@ -0,0 +1,29 @@
+/*
+ * 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");
+ }
+}
+