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https://issues.apache.org/jira/browse/WICKET-3136?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pedro Santos updated WICKET-3136:
---------------------------------
Attachment: test-WICKET-3136.patch
test case trying to serialize/deserialize an page with pagemap
> JVM 1.6 crash caused by WicketObjectOutputStream, ClassStreamHandler, and
> Page.writePageObject
> -----------------------------------------------------------------------------------------------
>
> Key: WICKET-3136
> URL: https://issues.apache.org/jira/browse/WICKET-3136
> Project: Wicket
> Issue Type: Bug
> Components: wicket
> Affects Versions: 1.4.12
> Environment: JVM 1.6.0_22, CentOS release 5.3 (Final) and Mac OS
> 10.6.4
> Reporter: Roland Groen
> Assignee: Johan Compagner
> Fix For: 1.4.14, 1.5-M4
>
> Attachments: hs_err_pid3145.log, test-WICKET-3136.patch
>
>
> The JVM 6u22 (1.6.0_22) crashes while clicking on a page in the wicket
> application. This is always the same page, but there are pages that function.
> When serializing a Page object with the pageMapName field set, a JVM 1.6
> crashes on a segmentation fault. The error message is:
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> # SIGSEGV (0xb) at pc=0xf44a859e, pid=3145, tid=2969234320
> #
> # JRE version: 6.0_22-b04
> # Java VM: Java HotSpot(TM) Server VM (17.1-b03 mixed mode linux-x86 )
> # Problematic frame:
> # J
> org.apache.wicket.util.io.WicketObjectOutputStream$HandleTable.hash(Ljava/lang/Object;)I
> #
> # If you would like to submit a bug report, please visit:
> # http://java.sun.com/webapps/bugreport/crash.jsp
> #
> What goes on (and it took some time to find it):
> The WicketObjectOutputStream has a field wich is called classHandler. This
> classHandler is suppose to match the class of the curObject.
> When Page.writePageObject is called AND the field Page.pageMapName is set,
> the method Page.writePageObject will call writeObject(pageMapName). This
> call will change the value of WicketObjectOutputStream.classHandler into the
> classHandler of java.lang.String somewhere in
> WicketObjectOutputStream.writeObjectOverride. What happens next is a true
> disaster. Though some abstractions (PageSerializer), the method
> WicketObjectOutputStream.defaultWriteObject will is called. This method
> states:
> classHandler.writeFields(this, curObject);
> and due to fact that classHandler is a class handler of java.lang.String and
> not the one of the curObject, an instance of FieldAndIndex belonging to
> String.value will be called with another object. This ends up at calling
> unsafe.getObject(object, index) (a native method) with the wrong object
> reference, something which is not a good idea with sun.misc.Unsafe. Every
> operation on the returned object will crash the JVM. Unfortunately the next
> in line to operate on the object is WicketObjectOutputStream.HandleTable.hash
> which also calls a native method called System.identityHashCode. This method
> is known for some JVM crashes, and has been attributed for the JVM crash for
> a while during the investigation into this JVM crash.
> The solutions:
> 1) Do not use the WicketObjectOutputStream/WicketObjectStreamFactory. Works.
> 2) The method org.apache.wicket.Page.writePageObject(ObjectOutputStream)
> should not do a s.writeObject(pageMapName), but a s.writeUTF(pageMapName)
> instead. This way, the WicketObjectOutputStream.classHandler will not get the
> wrong value. org.apache.wicket.Page.readPageObject(ObjectInputStream) should
> be matched, of course.
> 3) WicketObjectOutputStream.defaultWriteObject() should update/get the right
> classHandler reference, just as
> WicketObjectOutputStream.writeObjectOverride(Object) does. You might even
> consider dropping the field entirely.
> The last option seems the best to me, because calling a writeObject from
> writePageObject is not semantically incorrect, furthermore, there might be
> other instances of this.
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