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

[Daniel D. Daugherty]

 > http://cr.openjdk.java.net/~coleenp/8025238/

src/share/vm/classfile/javaClasses.cpp
     1804   if (method == NULL) {
     1805     // leave name and fileName null
     1806 java_lang_StackTraceElement::set_lineNumber(element(), -1);
         Is it possible to set the name and fileName to something?
         A caller may not be expecting those to be NULL.

         Also, holder->method_with_idnum(method_id) should be able to
         search the previous class version list and find the obsolete
         Method* that matches the 'method_id' value.

src/share/vm/prims/jvmtiRedefineClasses.cpp
     Better comment than the original.

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