epoll_wait produces an EINVAL error since 4.1.30 (#8350)

Motivation:

epoll_wait should work in 4.1.30 like it did in 4.1.29.

Modifications:

Revert Integer.MAX_VALUE back to MAX_SCHEDULED_TIMERFD_NS (999,999,999).
Add unit test.

Result:

epoll_wait will no longer throw EINVAL.

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java

@@ -35,7 +35,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Queue;
-import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
 
@@ -44,7 +43,7 @@ import static java.lang.Math.min;
 /**
  * {@link EventLoop} which uses epoll under the covers. Only works on Linux!
  */
-final class EpollEventLoop extends SingleThreadEventLoop {
+class EpollEventLoop extends SingleThreadEventLoop {
     private static final InternalLogger logger = InternalLoggerFactory.getInstance(EpollEventLoop.class);
     private static final AtomicIntegerFieldUpdater<EpollEventLoop> WAKEN_UP_UPDATER =
             AtomicIntegerFieldUpdater.newUpdater(EpollEventLoop.class, "wakenUp");
@@ -75,6 +74,7 @@ final class EpollEventLoop extends SingleThreadEventLoop {
             return epollWaitNow();
         }
     };
+    @SuppressWarnings("unused") // AtomicIntegerFieldUpdater
     private volatile int wakenUp;
     private volatile int ioRatio = 50;
 
@@ -248,7 +248,7 @@ final class EpollEventLoop extends SingleThreadEventLoop {
             long totalDelay = delayNanos(System.nanoTime());
             prevDeadlineNanos = curDeadlineNanos;
             delaySeconds = (int) min(totalDelay / 1000000000L, Integer.MAX_VALUE);
-            delayNanos = (int) min(totalDelay - delaySeconds * 1000000000L, Integer.MAX_VALUE);
+            delayNanos = (int) min(totalDelay - delaySeconds * 1000000000L, MAX_SCHEDULED_TIMERFD_NS);
         }
         return Native.epollWait(epollFd, events, timerFd, delaySeconds, delayNanos);
     }
@@ -356,7 +356,10 @@ final class EpollEventLoop extends SingleThreadEventLoop {
         }
     }
 
-    private static void handleLoopException(Throwable t) {
+    /**
+     * Visible only for testing!
+     */
+    void handleLoopException(Throwable t) {
         logger.warn("Unexpected exception in the selector loop.", t);
 
         // Prevent possible consecutive immediate failures that lead to

transport-native-epoll/src/test/java/io/netty/channel/epoll/EpollEventLoopTest.java

@@ -15,24 +15,41 @@
  */
 package io.netty.channel.epoll;
 
+import io.netty.channel.DefaultSelectStrategyFactory;
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
+import io.netty.util.concurrent.DefaultThreadFactory;
 import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.RejectedExecutionHandlers;
+import io.netty.util.concurrent.ThreadPerTaskExecutor;
 import org.junit.Test;
 
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 public class EpollEventLoopTest {
 
     @Test
     public void testScheduleBigDelayNotOverflow() {
-        EventLoopGroup group = new EpollEventLoopGroup(1);
+        final AtomicReference<Throwable> capture = new AtomicReference<Throwable>();
 
-        final EventLoop el = group.next();
-        Future<?> future = el.schedule(new Runnable() {
+        final EventLoopGroup group = new EpollEventLoop(null,
+                new ThreadPerTaskExecutor(new DefaultThreadFactory(getClass())), 0,
+                DefaultSelectStrategyFactory.INSTANCE.newSelectStrategy(), RejectedExecutionHandlers.reject()) {
+            @Override
+            void handleLoopException(Throwable t) {
+                capture.set(t);
+                super.handleLoopException(t);
+            }
+        };
+
+        try {
+            final EventLoop eventLoop = group.next();
+            Future<?> future = eventLoop.schedule(new Runnable() {
                 @Override
                 public void run() {
                     // NOOP
@@ -41,6 +58,9 @@ public class EpollEventLoopTest {
 
             assertFalse(future.awaitUninterruptibly(1000));
             assertTrue(future.cancel(true));
+            assertNull(capture.get());
+        } finally {
             group.shutdownGracefully();
         }
+    }
 }