RFR (S) 8025238: nsk/jvmti/scenarios/bcinstr/BI04/bi04t002 crashed with SIGSEGV

[Staffan Larsen]

On 4 okt 2013, at 00:49, Coleen Phillmore <coleen.phillimore at oracle.com> wrote:

> 
> Thanks Dan -
> 
> On 10/3/2013 4:28 PM, Daniel D. Daugherty wrote:
>> > open webrev at http://cr.openjdk.java.net/~coleenp/8025238_jdk
>> 
>> test/java/lang/instrument/RedefineMethodInBacktrace.sh
>>    No comments.
>> 
>> test/java/lang/instrument/RedefineMethodInBacktraceApp.java
>>    line 78:         t.setDaemon(true);
>>        Why make the target thread a daemon? Wouldn't it be a more
>>        complete test to do Thread.join() of that thread just to
>>        be sure that the target thread has finished (and is not
>>        stuck)?
> 
> Staffan, can you answer this?

You could do it either way. I don't have a strong opinion. It's possible that the deamonization is a leftover from one of my iterations of the test.

/Staffan


> 
> Coleen
> 
>> 
>> test/java/lang/instrument/RedefineMethodInBacktraceTargetB.java
>> test/java/lang/instrument/RedefineMethodInBacktraceTargetB_2.java
>>    Nice sync logic with the test driver.
>> 
>> Thumbs up.
>> 
>> Dan
>> 
>> 
>> On 10/3/13 12:02 PM, Coleen Phillimore wrote:
>>> Summary: Redefined class in stack trace may not be found by method_idnum so handle null.
>>> 
>>> This is a simple change.  I had another change to save the method name (as u2) in the backtrace, but it's not worth the extra footprint in backtraces for this rare case.
>>> 
>>> The root problem was that we save method_idnum in the backtrace (u2) instead of Method* to avoid Method* from being redefined and deallocated.  I made a change to InstanceKlass::method_from_idnum() to return null rather than the last method in the list, which causes this crash.   Dan and I went down the long rabbit-hole of why method_idnum is changed for obsolete methods and we think there's some cleanup and potential bugs in this area.  But this is not that change.  I'll file another bug to continue this investigation for jdk9 (or 8uN).
>>> 
>>> Staffan created a test - am including core-libs for the review request.  Also tested with all of the vm testbase tests, mlvm tests, and java/lang/instrument tests.
>>> 
>>> open webrev at http://cr.openjdk.java.net/~coleenp/8025238/
>>> bug link https://bugs.openjdk.java.net/browse/JDK-8025238
>>> 
>>> test case for jdk8 repository:
>>> 
>>> open webrev at http://cr.openjdk.java.net/~coleenp/8025238_jdk
>>> 
>>> Thanks,
>>> Coleen
>>> 
>>> 
>> 
>