JVM/TI code review request (XS and M) (7182152)

[serguei.spitsyn at oracle.com]

Dan,


The fixes look good for all 3 HS versions (modulo discussions with 
Coleen and Karen).
Great discovery, thank you for doing this!

Thanks,
Serguei



On 2/1/13 11:55 AM, Daniel D. Daugherty wrote:
> Greetings,
>
> I have a fix for the following JVM/TI bug:
>
>     7182152 Instrumentation hot swap test incorrect monitor count
>     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7182152
>     https://jbs.oracle.com/bugs/browse/JDK-7182152
>
> The fix for the bug in the product code is one line:
>
> src/share/vm/oops/klassVtable.cpp:
>
> @@ -992,18 +1020,50 @@
>            // RC_TRACE macro has an embedded ResourceMark
>            RC_TRACE(0x00200000, ("itable method update: %s(%s)",
>              new_method->name()->as_C_string(),
>              new_method->signature()->as_C_string()));
>          }
> -        break;
> +        // cannot 'break' here; see for-loop comment above.
>        }
>        ime++;
>      }
>    }
>  }
>
> and is applicable to JDK7u10/HSX-23.6 and JDK7u14/HSX-24. Coleen
> already fixed the bug as part of the Perm Gen Removal (PGR) project
> in HSX-25. Yes, we found a 1-line bug fix buried in the monster PGR
> changeset. Many thanks to Coleen for her help in this bug hunt!
>
> The rest of the code in the webrevs are:
>
> - additional JVM/TI tracing code backported from Coleen's PGR changeset
> - additional JVM/TI tracing code added by me and forward ported to HSX-25
> - a new -XX:TraceRedefineClasses=16384 flag value for finding these
>   elusive old or obsolete methods
> - exposure of some printing code to the PRODUCT build so that the new
>   tracing is available in a PRODUCT build
>
> You might be wondering why the new tracing code is exposed in a PRODUCT
> build. Well, it appears that more and more PRODUCT bits deployments are
> using JVM/TI RedefineClasses() and/or RetransformClasses() at run-time
> to instrument their systems. This bug (7182152) was only intermittently
> reproducible in the WLS environment in which it occurred so I made the
> tracing available in a PRODUCT build to assist in the hunt.
>
> Raj from the WLS team has also verified that the HSX-23.6 version of
> fix resolves the issue in his environment. Thanks Raj!
>
> Here are the URLs for the three webrevs:
>
> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx23.6/
> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx24/
> http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx25/
>
> I have run the following test suites from the JPDA stack on the
> JDK7u10/HSX-23.6 version of the fix with -XX:TraceRedefineClasses=16384
> specified:
>
>     sdk-jdi
>     sdk-jdi_closed
>     sdk-jli
>     vm-heapdump
>     vm-hprof
>     vm-jdb
>     vm-jdi
>     vm-jdwp
>     vm-jvmti
>     vm-sajdi
>
> The tested configs are:
>
>     {Solaris-X86, WinXP}
>       X {Client VM, Server VM}
>       X {-Xmixed, -Xcomp}
>       X {product, fastdebug}
>
> With the 1-liner fix in place, the new tracing code does not find any
> instances of this failure mode in any of the above test suites. Without
> the the 1-liner fix in place, the new tracing code finds one instance
> of this failure mode in the above test suites:
>
>     test/java/lang/instrument/IsModifiableClassAgent.java
>
> There are two new tests that will be pushed to the JDK repos using
> a different bug ID (not yet filed):
>
>     test/com/sun/jdi/RedefineAbstractClass.sh
> test/java/lang/instrument/RedefineSubclassWithTwoInterfaces.sh
>
> There will be a separate review request for the new tests.
>
> I'm currently running the JPDA stack of tests on the JDK7u14/HSX-24
> and JDK8-B75/HSX-25 versions of the fix. That testing will likely
> take all weekend to complete.
>
> Thanks, in advance, for any comments and/or suggestions.
>
> Dan
>