7122142 : (ann) Race condition between isAnnotationPresent and getAnnotations

[Peter Levart]

On 06/19/2013 08:54 PM, Alan Bateman wrote:
> Thank you for coming back to this.
>
> I've looked over the webrev and the approach looks good to me. Joel 
> might want to look at this too. Do you think you could include a test 
> (as we try to include a test with all fixes if we can)?
>
> It would be good to remove the synchronizaiton on 
> initAnnotationsIfNecessary too, but one step as time (and smaller 
> changes are always easier to discuss).
>
> -Alan

Hi Alan,

I have prepared the 2nd revision of the patch:

http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.02/

There is a little change in AnnotationParser's alternative parsing 
method. This time the parser does not assume anything about annotations 
being parsed (previously it assumed that they had RUNTIME retention). 
The only difference from standard parsing is that only the select 
annotation types are parsed and the rest are quickly skipped. Infinite 
recursion is broken by the special cased evaluation in AnnotationType 
constructor:

  129         // Initialize retention, & inherited fields.  Special treatment
  130         // of the corresponding annotation types breaks infinite recursion.
  131         if (annotationClass != Retention.class &&
  132             annotationClass != Inherited.class) {
  133             JavaLangAccess jla = sun.misc.SharedSecrets.getJavaLangAccess();
  134             Map<Class<? extends Annotation>, Annotation> metaAnnotations =
  135                 AnnotationParser.parseAnnotations(
  136                     jla.getRawClassAnnotations(annotationClass),
  137                     jla.getConstantPool(annotationClass),
  138                     annotationClass,
  139                     Retention.class, Inherited.class
  140                 );
  141             Retention ret = (Retention) metaAnnotations.get(Retention.class);
  142             retention = (ret == null ? RetentionPolicy.CLASS : ret.value());
  143             inherited = metaAnnotations.containsKey(Inherited.class);
  144         }
  145         else {
  146             retention = RetentionPolicy.RUNTIME;
  147             inherited = false;
  148         }


This is enough to break recursion. The RUNTIME and !inherited 
assumptions for @Retention and @Inherited meta-annotations are therefore 
localized in this code only.

I have also added two tests. The one for detecting deadlock situation 
and the other for consistent parsing of mutually recursive annotations 
in presence of separate compilation.



Regards, Peter