[HTTPCORE-336] Unhandled CancelledKeyException leads to a shutdown of the underlying IOReactor

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.2.3
• Fix Version/s: 4.3-beta2
• Component/s: HttpCore NIO
• Environment: HttpAsyncClient 4.0-beta3
• Assignee: Unassigned
• Reporter: Thomas Dudek
• Created: 27/Mar/13 11:44
• Updated: 05/Oct/13 20:09
• Resolved: 02/Apr/13 16:12

Description

An unhandled java.nio.channels.CancelledKeyException in AbstractIOReactor#processNewChannels() leads to a shutdown of the underlying IOReactor.

Here's the stacktrace:

org.apache.http.nio.reactor.IOReactorException: I/O dispatch worker terminated abnormally
 at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:382)
 at org.apache.http.impl.nio.conn.PoolingClientAsyncConnectionManager.execute(PoolingClientAsyncConnectionManager.java:108)
 at org.apache.http.impl.nio.client.AbstractHttpAsyncClient.doExecute(AbstractHttpAsyncClient.java:464)
 at org.apache.http.impl.nio.client.AbstractHttpAsyncClient.access$000(AbstractHttpAsyncClient.java:101)
 at org.apache.http.impl.nio.client.AbstractHttpAsyncClient$1.run(AbstractHttpAsyncClient.java:485)
Caused by: java.nio.channels.CancelledKeyException
 at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:73)
 at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:77)
 at org.apache.http.impl.nio.reactor.IOSessionImpl.<init>(IOSessionImpl.java:94)
 at org.apache.http.impl.nio.reactor.AbstractIOReactor.processNewChannels(AbstractIOReactor.java:406)
 at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:291)
 at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
 at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:604)
 at java.lang.Thread.run(Thread.java:722)

This happens regularly under non-reproducible circumstances.
The particular line of code where the exception is not handled is AbstractIOReactor.java:406. The exception is thrown in the constructor of IOSessionImpl.java:94 in order of a canceled SelectionKey.

As a result of this unhandled exception, the AbstractMultiworkerIOReactor throws a IOReactorException in AbstractMultiworkerIOReactor.java:382 and is finally being shutdown.

Since this component is used by HttpAsyncClient, after this exception the instance of HttpAsyncClient is no longer usable.

The following patch works for us (AbstractIOReactor.java:406):

IOSession session = null;
try {
	session = new IOSessionImpl(key, interestOpsCallback, sessionClosedCallback);
} catch (CancelledKeyException ex) {
	key.attach(null);
	return;
}