OpenJDK7 jmap UnalignedAddressException

[Andrew]

I'm running a 9-STABLE on AMD64 machine with the port java/openjdk7
installed and when I execute jmap against a running java process of
the same JDK running under the same (non-root) user or running jmap as
root I get the following exception:

Attaching to process ID 97337, please wait...
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at sun.tools.jmap.JMap.runTool(JMap.java:197)
        at sun.tools.jmap.JMap.main(JMap.java:128)
Caused by: sun.jvm.hotspot.debugger.UnalignedAddressException: 746f705b75af4867
        at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$1.checkAlignment(BsdDebuggerLocal.java:181)
        at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.readCInteger(BsdDebuggerLocal.java:478)
        at sun.jvm.hotspot.debugger.DebuggerBase.readAddressValue(DebuggerBase.java:454)
        at sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.readAddress(BsdDebuggerLocal.java:423)
        at sun.jvm.hotspot.debugger.bsd.BsdAddress.getAddressAt(BsdAddress.java:74)
        at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:154)
        at sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:85)
        at sun.jvm.hotspot.bugspot.BugSpotAgent.setupVM(BugSpotAgent.java:572)
        at sun.jvm.hotspot.bugspot.BugSpotAgent.go(BugSpotAgent.java:493)
        at sun.jvm.hotspot.bugspot.BugSpotAgent.attach(BugSpotAgent.java:331)
        at sun.jvm.hotspot.tools.Tool.start(Tool.java:163)
        at sun.jvm.hotspot.tools.PMap.main(PMap.java:67)
        ... 6 more

uname: FreeBSD 9.0-STABLE #0: Thu Apr 12 10:59:45 BST 2012
Java:
 /usr/local/openjdk7/bin/java -version
openjdk version "1.7.0_02"
OpenJDK Runtime Environment (build 1.7.0_02-b13)
OpenJDK 64-Bit Server VM (build 22.0-b10, mixed mode)


Has anyone else seen this error?

Thanks,
Andrew