[FTPSERVER-403] FTP would periodically hang in MDC

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.3, 1.0.4, 1.0.5, 1.0.6
• Fix Version/s: 1.0.0-M1, 1.1.0
• Component/s: Core, Server
• Environment: Encountered it both on Linux and FreeBSD, both on Sun JVM 1.6 and OpenJDK 6.
• Assignee: Niklas Therning
• Reporter: ArtemGr
• Created: 07/Mar/11 13:08
• Updated: 31/Oct/16 14:43
• Resolved: 02/Nov/11 08:29

Description

FTP works fine for the most time but once in a while (depended on how often the FTP is used) it would hang, consuming 100% CPU, in
java.util.HashMap.removeEntryForKey (HashMap.java:586)
java.util.HashMap.remove (HashMap.java:555)
org.slf4j.helpers.BasicMDCAdapter.remove (BasicMDCAdapter.java:91)
org.slf4j.MDC.remove (MDC.java:156)
org.apache.mina.filter.logging.MdcInjectionFilter.filter (MdcInjectionFilter.java:141)
org.apache.mina.filter.util.CommonEventFilter.messageSent (CommonEventFilter.java:75)
org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageSent (DefaultIoFilterChain.java:462)
org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1300 (DefaultIoFilterChain.java:46)
org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageSent (DefaultIoFilterChain.java:802)
org.apache.mina.filter.codec.ProtocolCodecFilter.messageSent (ProtocolCodecFilter.java:287)
org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageSent (DefaultIoFilterChain.java:462)
org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1300 (DefaultIoFilterChain.java:46)
org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageSent (DefaultIoFilterChain.java:802)
org.apache.mina.core.filterchain.IoFilterEvent.fire (IoFilterEvent.java:80)
org.apache.mina.core.session.IoEvent.run (IoEvent.java:63)
org.apache.mina.filter.executor.OrderedThreadPoolExecutor$Worker.runTask (OrderedThreadPoolExecutor.java:780)
org.apache.mina.filter.executor.OrderedThreadPoolExecutor$Worker.runTasks (OrderedThreadPoolExecutor.java:772)
org.apache.mina.filter.executor.OrderedThreadPoolExecutor$Worker.run (OrderedThreadPoolExecutor.java:714)
java.lang.Thread.run (Thread.java:636)

Seems like a synchronization issue to me.