PING: Unexpected ArithmeticException at sun.jvm.hotspot.utilities.CompactHashTable

[KUBOTA Yuji]

Dmitry,

Thank you for your kindly sponsorship!

- Yuji


2016-03-07 20:48 GMT+09:00 Dmitry Samersoff <dmitry.samersoff at oracle.com>:
> Yuji,
>
> CR number is JDK-8151368
>
> -Dmitry
>
> On 2016-02-22 15:31, KUBOTA Yuji wrote:
>> Hi all,
>>
>> Could you please review this patch?
>> I do not have any account at openjdk now, so I need a sponsor.
>>
>> Thanks,
>> Yuji
>>
>> 2015-12-18 15:27 GMT+09:00 KUBOTA Yuji <kubota.yuji at gmail.com>:
>>> Hi all,
>>>
>>> I caught an unexpected java.lang.ArithmeticException by CLHSDB through
>>> jhsdb as below.
>>>
>>> -----
>>> ./jhsdb clhsdb --pid 16809
>>> Attaching to process 16809, please wait...
>>> hsdb> class java/lang/ArithmeticException
>>> java/lang/ArithmeticException @0x0000000100011958
>>> hsdb> class java
>>> class not found: java
>>> hsdb> class java/lang
>>> Error: java.lang.ArithmeticException: / by zero
>>> -----
>>>
>>> I think that CLHSDB returns "class not found: java/lang". But
>>> ArithmetricException is returned instead.
>>> CLHSDB tries to search the given class name from the regular symbol
>>> table and the shared symbol table.
>>> And called the probe function of the shared symbol table does not
>>> support a case of the empty bucket such as below expression
>>>
>>>> long index = hash % bucketCount();
>>>
>>> then, throws ArithmetricException.
>>>
>>> The stack trace of this java.lang.ArithmeticException is here.
>>> ------
>>> java.lang.ArithmeticException: / by zero
>>>         at sun.jvm.hotspot.utilities.CompactHashTable.probe(CompactHashTable.java:89)
>>>         at sun.jvm.hotspot.memory.SymbolTable.probe(SymbolTable.java:97)
>>>         at sun.jvm.hotspot.memory.SymbolTable.probe(SymbolTable.java:75)
>>>         at sun.jvm.hotspot.memory.SystemDictionary.find(SystemDictionary.java:149)
>>>         at sun.jvm.hotspot.utilities.SystemDictionaryHelper.findInstanceKlass(SystemDictionaryHelper.java:107)
>>>         at jdk.nashorn.internal.scripts.Script$Recompilation$2402$7541A$sa.main$jclass(sa.js:247)
>>>         at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:625)
>>>         at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:511)
>>>         at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
>>>         at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:199)
>>>         at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:383)
>>>         at jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction(NashornScriptEngine.java:190)
>>>         at sun.jvm.hotspot.utilities.soql.JSJavaScriptEngine.call(JSJavaScriptEngine.java:78)
>>>         at sun.jvm.hotspot.CommandProcessor$52.doit(CommandProcessor.java:1755)
>>>         at sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:1951)
>>>         at sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:1921)
>>>         at sun.jvm.hotspot.CommandProcessor.run(CommandProcessor.java:1801)
>>>         at sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:99)
>>>         at sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:40)
>>>         at sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:134)
>>>         at sun.jvm.hotspot.SALauncher.main(SALauncher.java:334)
>>> ------
>>>
>>> I have created a patch from jdk9/dev/hotspot (changeset:
>>> 9625:de592ea5f7ba) as below, and checked to return "class not found
>>> java/lang" correctly. Please review it.
>>>
>>> diff --git a/agent/src/share/classes/sun/jvm/hotspot/utilities/CompactHashTable.java
>>> b/agent/src/share/classes/sun/jvm/hotspot/utilities/CompactHashTable.java
>>> --- a/agent/src/share/classes/sun/jvm/hotspot/utilities/CompactHashTable.java
>>> +++ b/agent/src/share/classes/sun/jvm/hotspot/utilities/CompactHashTable.java
>>> @@ -86,6 +86,10 @@
>>>      Address baseAddress = baseAddressField.getValue(addr);
>>>      Address bucket = bucketsField.getValue(addr);
>>>      Address bucketEnd = bucket;
>>> +
>>> +    if (bucketCount() == 0) {
>>> +      return null;
>>> +    }
>>>      long index = hash % bucketCount();
>>>      int bucketInfo = (int)bucket.getCIntegerAt(index * uintSize,
>>> uintSize, true);
>>>      int bucketOffset = bucketOffset(bucketInfo);
>>>
>>>
>>> Thanks,
>>> Yuji
>
>
> --
> Dmitry Samersoff
> Oracle Java development team, Saint Petersburg, Russia
> * I would love to change the world, but they won't give me the sources.