[HTTPCORE-605] Infinite loop on half close

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Cannot Reproduce
• Affects Version/s: 4.4.11
• Component/s: HttpCore NIO
• Assignee: Unassigned
• Reporter: Hunter Presnall
• Created: 08/Oct/19 17:43
• Updated: 14/Oct/19 13:43
• Resolved: 14/Oct/19 12:58

Description

When the server half-closes the connection, the http client gets stuck in an infinite loop with a writable selection key, but no data to send. They selection key is never cleared and empty buffers are continually sent.

The stack trace when this happens is:

"I/O dispatcher 2" #30 prio=5 os_prio=0 tid=0x00007fd7cc0a5000 nid=0x2c runnable [0x00007fd7db6fb000]"I/O dispatcher 2" #30 prio=5 os_prio=0 tid=0x00007fd7cc0a5000 nid=0x2c runnable [0x00007fd7db6fb000]   java.lang.Thread.State: RUNNABLE at sun.nio.ch.NativeThread.current(Native Method) at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:468) - locked <0x0000000091fb63b0> (a java.lang.Object) - locked <0x0000000091fb63a0> (a java.lang.Object) at org.apache.http.nio.reactor.ssl.SSLIOSession.sendEncryptedData(SSLIOSession.java:423) at org.apache.http.nio.reactor.ssl.SSLIOSession.outboundTransport(SSLIOSession.java:549) - locked <0x0000000091fb6630> (a org.apache.http.nio.reactor.ssl.SSLIOSession) at org.apache.http.impl.nio.reactor.AbstractIODispatch.outputReady(AbstractIODispatch.java:154) at org.apache.http.impl.nio.reactor.BaseIOReactor.writable(BaseIOReactor.java:188) at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:341) at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315) at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276) at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104) at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:591) at java.lang.Thread.run(Thread.java:748)

 

This is similar to HTTPCORE-528  which was fixed in 4.4.10. When we upgraded the client to 4.4.11, this new issue appeared. I suspect similar handling where there is write interest but no data needs to remove the write mask.