HADOOP-11604. Prevent ConcurrentModificationException while closing domain sockets during shutdown of DomainSocketWatcher thread. Contributed by Chris Nauroth.

(cherry picked from commit 3c5ff0759c)
(cherry picked from commit 187e081d5a)
This commit is contained in:
cnauroth 2015-02-20 13:07:16 -08:00 committed by Vinod Kumar Vavilapalli
parent 02e0b6e306
commit 342504f790
3 changed files with 105 additions and 8 deletions

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@ -42,6 +42,9 @@ Release 2.6.1 - UNRELEASED
HADOOP-11295. RPC Server Reader thread can't shutdown if RPCCallQueue is
full. (Ming Ma via kihwal)
HADOOP-11604. Prevent ConcurrentModificationException while closing domain
sockets during shutdown of DomainSocketWatcher thread. (cnauroth)
Release 2.6.0 - 2014-11-18
INCOMPATIBLE CHANGES

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@ -246,6 +246,13 @@ public final class DomainSocketWatcher implements Closeable {
this.interruptCheckPeriodMs = interruptCheckPeriodMs;
notificationSockets = DomainSocket.socketpair();
watcherThread.setDaemon(true);
watcherThread.setUncaughtExceptionHandler(
new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread thread, Throwable t) {
LOG.error(thread + " terminating on unexpected exception", t);
}
});
watcherThread.start();
}
@ -372,7 +379,17 @@ public final class DomainSocketWatcher implements Closeable {
}
}
private void sendCallback(String caller, TreeMap<Integer, Entry> entries,
/**
* Send callback and return whether or not the domain socket was closed as a
* result of processing.
*
* @param caller reason for call
* @param entries mapping of file descriptor to entry
* @param fdSet set of file descriptors
* @param fd file descriptor
* @return true if the domain socket was closed as a result of processing
*/
private boolean sendCallback(String caller, TreeMap<Integer, Entry> entries,
FdSet fdSet, int fd) {
if (LOG.isTraceEnabled()) {
LOG.trace(this + ": " + caller + " starting sendCallback for fd " + fd);
@ -401,13 +418,30 @@ public final class DomainSocketWatcher implements Closeable {
"still in the poll(2) loop.");
}
IOUtils.cleanup(LOG, sock);
entries.remove(fd);
fdSet.remove(fd);
return true;
} else {
if (LOG.isTraceEnabled()) {
LOG.trace(this + ": " + caller + ": sendCallback not " +
"closing fd " + fd);
}
return false;
}
}
/**
* Send callback, and if the domain socket was closed as a result of
* processing, then also remove the entry for the file descriptor.
*
* @param caller reason for call
* @param entries mapping of file descriptor to entry
* @param fdSet set of file descriptors
* @param fd file descriptor
*/
private void sendCallbackAndRemove(String caller,
TreeMap<Integer, Entry> entries, FdSet fdSet, int fd) {
if (sendCallback(caller, entries, fdSet, fd)) {
entries.remove(fd);
}
}
@ -427,7 +461,8 @@ public final class DomainSocketWatcher implements Closeable {
lock.lock();
try {
for (int fd : fdSet.getAndClearReadableFds()) {
sendCallback("getAndClearReadableFds", entries, fdSet, fd);
sendCallbackAndRemove("getAndClearReadableFds", entries, fdSet,
fd);
}
if (!(toAdd.isEmpty() && toRemove.isEmpty())) {
// Handle pending additions (before pending removes).
@ -448,7 +483,7 @@ public final class DomainSocketWatcher implements Closeable {
while (true) {
Map.Entry<Integer, DomainSocket> entry = toRemove.firstEntry();
if (entry == null) break;
sendCallback("handlePendingRemovals",
sendCallbackAndRemove("handlePendingRemovals",
entries, fdSet, entry.getValue().fd);
}
processedCond.signalAll();
@ -482,6 +517,8 @@ public final class DomainSocketWatcher implements Closeable {
try {
kick(); // allow the handler for notificationSockets[0] to read a byte
for (Entry entry : entries.values()) {
// We do not remove from entries as we iterate, because that can
// cause a ConcurrentModificationException.
sendCallback("close", entries, fdSet, entry.getDomainSocket().fd);
}
entries.clear();

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@ -17,6 +17,8 @@
*/
package org.apache.hadoop.net.unix;
import static org.junit.Assert.assertFalse;
import java.util.ArrayList;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
@ -25,6 +27,7 @@ import java.util.concurrent.locks.ReentrantLock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.junit.After;
import org.junit.Assume;
import org.junit.Before;
import org.junit.Test;
@ -34,11 +37,22 @@ import com.google.common.util.concurrent.Uninterruptibles;
public class TestDomainSocketWatcher {
static final Log LOG = LogFactory.getLog(TestDomainSocketWatcher.class);
private Throwable trappedException = null;
@Before
public void before() {
Assume.assumeTrue(DomainSocket.getLoadingFailureReason() == null);
}
@After
public void after() {
if (trappedException != null) {
throw new IllegalStateException(
"DomainSocketWatcher thread terminated with unexpected exception.",
trappedException);
}
}
/**
* Test that we can create a DomainSocketWatcher and then shut it down.
*/
@ -79,6 +93,24 @@ public class TestDomainSocketWatcher {
watcher.close();
}
/**
* Test that domain sockets are closed when the watcher is closed.
*/
@Test(timeout=300000)
public void testCloseSocketOnWatcherClose() throws Exception {
final DomainSocketWatcher watcher = newDomainSocketWatcher(10000000);
DomainSocket pair[] = DomainSocket.socketpair();
watcher.add(pair[1], new DomainSocketWatcher.Handler() {
@Override
public boolean handle(DomainSocket sock) {
return true;
}
});
watcher.close();
Uninterruptibles.joinUninterruptibly(watcher.watcherThread);
assertFalse(pair[1].isOpen());
}
@Test(timeout=300000)
public void testStress() throws Exception {
final int SOCKET_NUM = 250;
@ -148,4 +180,29 @@ public class TestDomainSocketWatcher {
Uninterruptibles.joinUninterruptibly(removerThread);
watcher.close();
}
/**
* Creates a new DomainSocketWatcher and tracks its thread for termination due
* to an unexpected exception. At the end of each test, if there was an
* unexpected exception, then that exception is thrown to force a failure of
* the test.
*
* @param interruptCheckPeriodMs interrupt check period passed to
* DomainSocketWatcher
* @return new DomainSocketWatcher
* @throws Exception if there is any failure
*/
private DomainSocketWatcher newDomainSocketWatcher(int interruptCheckPeriodMs)
throws Exception {
DomainSocketWatcher watcher = new DomainSocketWatcher(
interruptCheckPeriodMs);
watcher.watcherThread.setUncaughtExceptionHandler(
new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread thread, Throwable t) {
trappedException = t;
}
});
return watcher;
}
}