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Posted to dev@tomcat.apache.org by bu...@apache.org on 2011/06/01 14:21:28 UTC
DO NOT REPLY [Bug 51306] New: NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
Bug #: 51306
Summary: NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when
handling remote session expiration
Product: Tomcat 6
Version: 6.0.32
Platform: PC
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P2
Component: Cluster
AssignedTo: dev@tomcat.apache.org
ReportedBy: mikhailov.dmitry@gmail.com
Classification: Unclassified
Occasionally we got errors like following:
======
2011-05-30 03:40:17,697 ERROR [pool-1-thread-2]
(org.apache.catalina.ha.session.DeltaManager) Manager [localhost#]: Unable to
receive message through TCP channel
java.lang.NullPointerException
at
java.io.ObjectOutputStream$BlockDataOutputStream.getUTFLength(ObjectOutputStream.java:2106)
at
java.io.ObjectOutputStream$BlockDataOutputStream.writeUTF(ObjectOutputStream.java:1977)
at java.io.ObjectOutputStream.writeUTF(ObjectOutputStream.java:849)
at
org.apache.catalina.ha.session.DeltaRequest.writeExternal(DeltaRequest.java:267)
at org.apache.catalina.ha.session.DeltaRequest.serialize(DeltaRequest.java:287)
at
org.apache.catalina.ha.session.DeltaManager.serializeDeltaRequest(DeltaManager.java:716)
at
org.apache.catalina.ha.session.DeltaManager.requestCompleted(DeltaManager.java:1224)
at org.apache.catalina.ha.session.DeltaSession.expire(DeltaSession.java:403)
at
org.apache.catalina.ha.session.DeltaManager.handleSESSION_EXPIRED(DeltaManager.java:1546)
at
org.apache.catalina.ha.session.DeltaManager.messageReceived(DeltaManager.java:1452)
at
org.apache.catalina.ha.session.DeltaManager.messageDataReceived(DeltaManager.java:1173)
at
org.apache.catalina.ha.session.ClusterSessionListener.messageReceived(ClusterSessionListener.java:92)
at
org.apache.catalina.ha.tcp.SimpleTcpCluster.messageReceived(SimpleTcpCluster.java:901)
at
org.apache.catalina.ha.tcp.SimpleTcpCluster.messageReceived(SimpleTcpCluster.java:882)
at
org.apache.catalina.tribes.group.GroupChannel.messageReceived(GroupChannel.java:269)
at
org.apache.catalina.tribes.group.ChannelInterceptorBase.messageReceived(ChannelInterceptorBase.java:79)
at
org.apache.catalina.tribes.group.interceptors.TcpFailureDetector.messageReceived(TcpFailureDetector.java:110)
at
org.apache.catalina.tribes.group.ChannelInterceptorBase.messageReceived(ChannelInterceptorBase.java:79)
at
org.apache.catalina.tribes.group.ChannelInterceptorBase.messageReceived(ChannelInterceptorBase.java:79)
at
org.apache.catalina.tribes.group.ChannelCoordinator.messageReceived(ChannelCoordinator.java:241)
at
org.apache.catalina.tribes.transport.ReceiverBase.messageDataReceived(ReceiverBase.java:225)
at
org.apache.catalina.tribes.transport.nio.NioReplicationTask.drainChannel(NioReplicationTask.java:188)
at
org.apache.catalina.tribes.transport.nio.NioReplicationTask.run(NioReplicationTask.java:91)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
It looks like the functionality of Tomcat is not affected by this.
The NPE comes from trying to write null sessionId, but why does Tomcat try to
send something from handling received authoritative SESSION_EXPIRED message?
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #5 from Keiichi Fujino <kf...@apache.org> 2011-06-13 09:52:21 UTC ---
Fixed in 7.0.x and will be included in 7.0.17 onwards.
Proposed for 6.0.x
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #4 from Keiichi Fujino <kf...@apache.org> 2011-06-13 08:57:57 UTC ---
There seem to be two problems in this stack trace.
The first problem is DeltaRequest#getSize() > 1 in non-primary node .
Usually, DeltaRequest#getSize() must be 0 in non-primary node. and, r818062
works correctly.
However, r818062 doesn't work correctly because DeltaRequest#getSize() is more
than 1 in this case.
This is a potential bug.
The second problem is DeltaRequest#sessionId() is null in non-primary node .
When handleSESSION_CREATED is completed, DeltaRequest#sessionId is always
non-null.
When setMaxInactiveInterval is called in handleSESSION_CREATED, the action is
added to DeltaRequest.
As a result, it becomes DeltaRequest#getSize() >1.
This is probably bug.
For instance, when handleSESSION_EXPIRED is processed while processing
handleSESSION_CREATED,
sessionId of DeltaRequest will become null and DeltaRequest#getSize() > 1.
And, NPE will be thrown out.
The workaround is..
Correct these bugs or Synchronize between handleSESSION_CREATED and
handleSESSION_EXPIRED.
I will correct not to add action to DeltaRequest when setMaxInactiveInterval is
called in handleSESSION_CREATED.
Additionally, I will correct the potential bug of r818062.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
Ronald Klop <ro...@echteman.nl> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ronald@echteman.nl
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #3 from Dmitry Mikhaylov <mi...@gmail.com> 2011-06-07 07:46:49 UTC ---
I'm not sure http://svn.apache.org/viewvc?view=revision&revision=818062
explains what is happening. While what the comment says is totally true, the
stack trace I pasted shows that the problem happens on *secondary nodes*: while
handling received remove session expiration event, for some reasons
DeltaManager tries to broadcast it to the whole cluster again.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #2 from Dmitry Mikhaylov <mi...@gmail.com> 2011-06-07 07:46:15 UTC ---
Our clusters vary in size from 2 to 11 Tomcats, these problems happen in all
configurations.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #8 from Ronald Klop <ro...@echteman.nl> 2011-06-15 08:59:35 UTC ---
I have customers who are 'logged out' in their words and that correlates with
the times of these errors in the logs. No hard evidence though.
And the weirdest thing is that it only happens since two or three weeks.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #6 from Ronald Klop <ro...@echteman.nl> 2011-06-14 10:37:39 UTC ---
Is there a workaround for this issue? What should I not do in my code to
prevent this?
The cause r818062 is from 2009, so I must go back very far to get a Tomcat
version which doesn't have this bug, with the risk, that I get back old bugs.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #10 from Dmitry Mikhaylov <mi...@gmail.com> 2011-06-28 09:16:36 UTC ---
Thanks a lot!
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #1 from Mark Thomas <ma...@apache.org> 2011-06-02 17:37:37 UTC ---
http://svn.apache.org/viewvc?view=revision&revision=818062 explains why this
code is here.
It looks like a race condition to me at the moment but more research is
required.
Just for background, how many nodes are there in your cluster?
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
Keiichi Fujino <kf...@apache.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
--- Comment #9 from Keiichi Fujino <kf...@apache.org> 2011-06-21 11:36:50 UTC ---
This has been fixed in 6.0.x and will be included in 6.0.33 onwards.
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DO NOT REPLY [Bug 51306] NPE in
DeltaRequest.writeExternal(DeltaRequest.java:267) when handling remote
session expiration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=51306
--- Comment #7 from Filip Hanik <fh...@apache.org> 2011-06-15 01:50:50 UTC ---
It's a bug in Tomcat, some funky cyclic implementation that I still fully don't
understand. Invoking listeners on expiring sessions....maybe valid...maybe not
needed....
However, does this bug really cause a problem in your app? The session is going
to expire no matter what, even if this error message is printed.
Besides the error message in the log, is your app actually experiencing any
symptoms from this?
best
Filip
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