7122142 : (ann) Race condition between isAnnotationPresent and getAnnotations (original) (raw)

Peter Levart peter.levart at gmail.com
Mon Jun 24 18:23:59 UTC 2013

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

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