RFR (S) 8025238: nsk/jvmti/scenarios/bcinstr/BI04/bi04t002 crashed with SIGSEGV
Coleen Phillmore
coleen.phillimore at oracle.com
Thu Oct 3 22:49:52 UTC 2013
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?
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
>>
>>
>
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