4-th round RFR (XS) 8068162: jvmtiRedefineClasses.cpp: guarantee(false) failed: OLD and/or OBSOLETE method(s) found

serguei.spitsyn at oracle.com serguei.spitsyn at oracle.com
Fri Jan 16 19:14:09 UTC 2015

Dan, David H. or David C.,

May I ask one of you to look at the webrev below?
The issue itself is a little bit tricky, so it is not easy to review 
despite the small size.


Does the webrev matches what we discussed with you?
Do you give me a thumbs up?


May I ask

On 1/13/15 9:47 PM, serguei.spitsyn at oracle.com wrote:
> Please, review the fix for:
>   https://bugs.openjdk.java.net/browse/JDK-8068162
> Open webrevs:
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/hotspot/8068162-JVMTI-old.4/ 
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/jdk/8068162-Test-IsModifiableAgent/ 
> Summary:
>    The sun.misc.Unsafe:throwIllegalAccessError() method is used in 
> place of a default
>    interface method in the itable if a default method was not defined 
> in the interface.
>    In fact, it happens for two interfaces that purhaps are 
> auto-generated:
>      java/nio/CharBuffer
>      java/nio/HeapCharBuffer
>    This approach creates a problem when the class sun.misc.Unsafe is 
> retransformed.
>    The Method* pointer to the old (redefined) method in the itable 
> triggers an assert
>    (see the hs_err log in the bug report).
>    Coleen told me that a similar approach is going to be implemented 
> for some vtable entries.
>    Coleen, thanks for suggesting a better fix for this issue!
>    The fix is to replace the old Unsafe method in the itable/vtable 
> with the latest method version.
> Testing:
>   In progress: nsk.jdi.testlist, JTREG java/lang/instrument tests
> Thanks,
> Serguei

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