Program: 82171
Project: 82171
Buggy source:
/** 
 * The way this method is called via warm up methods the likelihood of creating multiple bitsets during a race condition is very low, that's why this method is not synced.
 */
public static OpenBitSet getPrimeDocBitSet(Term primeDocTerm,AtomicReader providedReader) throws IOException {
  AtomicReader reader=AtomicReaderUtil.getSegmentReader(providedReader);
  final Object key=reader.getCoreCacheKey();
  final Map<Object,OpenBitSet> primeDocMap=getPrimeDocMap(primeDocTerm);
  OpenBitSet bitSet=primeDocMap.get(key);
  if (bitSet == null) {
synchronized (reader) {
      reader.addReaderClosedListener(new ReaderClosedListener(){
        @Override public void onClose(        IndexReader reader){
          LOG.debug("String_Node_Str" + primeDocMap.size() + "String_Node_Str"+ reader+ "String_Node_Str");
          OpenBitSet openBitSet=primeDocMap.remove(key);
          if (openBitSet == null) {
            LOG.warn("String_Node_Str",key);
          }
        }
      }
);
      LOG.debug("String_Node_Str" + reader + "String_Node_Str"+ primeDocMap.size()+ "String_Node_Str");
      final OpenBitSet bs=new OpenBitSet(reader.maxDoc());
      Fields fields=reader.fields();
      if (fields == null) {
        throw new IOException("String_Node_Str");
      }
      Terms terms=fields.terms(primeDocTerm.field());
      if (terms == null) {
        throw new IOException("String_Node_Str" + primeDocTerm.field() + "String_Node_Str");
      }
      TermsEnum termsEnum=terms.iterator(null);
      if (!termsEnum.seekExact(primeDocTerm.bytes(),true)) {
        throw new IOException("String_Node_Str" + primeDocTerm + "String_Node_Str");
      }
      DocsEnum docsEnum=termsEnum.docs(null,null);
      int docFreq=reader.docFreq(primeDocTerm);
      int doc;
      int count=0;
      while ((doc=docsEnum.nextDoc()) != DocIdSetIterator.NO_MORE_DOCS) {
        bs.fastSet(doc);
        count++;
      }
      if (count == docFreq) {
        primeDocMap.put(key,bs);
      }
 else {
        LOG.warn("String_Node_Str",reader,count,docFreq);
      }
      return bs;
    }
  }
  return bitSet;
}

Fixed version (ground truth):
/** 
 * The way this method is called via warm up methods the likelihood of creating multiple bitsets during a race condition is very low, that's why this method is not synced.
 */
public static OpenBitSet getPrimeDocBitSet(Term primeDocTerm,AtomicReader providedReader) throws IOException {
  AtomicReader reader=AtomicReaderUtil.getSegmentReader(providedReader);
  final Object key=reader.getCoreCacheKey();
  final Map<Object,OpenBitSet> primeDocMap=getPrimeDocMap(primeDocTerm);
  OpenBitSet bitSet=primeDocMap.get(key);
  if (bitSet == null) {
synchronized (reader) {
      reader.addReaderClosedListener(new ReaderClosedListener(){
        @Override public void onClose(        IndexReader reader){
          LOG.debug("String_Node_Str" + primeDocMap.size() + "String_Node_Str"+ reader+ "String_Node_Str");
          OpenBitSet openBitSet=primeDocMap.remove(key);
          if (openBitSet == null) {
            LOG.warn("String_Node_Str",key);
          }
        }
      }
);
      LOG.debug("String_Node_Str" + reader + "String_Node_Str"+ primeDocMap.size()+ "String_Node_Str");
      final OpenBitSet bs=new OpenBitSet(reader.maxDoc());
      MemoryLeakDetector.record(bs,"String_Node_Str",key.toString());
      Fields fields=reader.fields();
      if (fields == null) {
        throw new IOException("String_Node_Str");
      }
      Terms terms=fields.terms(primeDocTerm.field());
      if (terms == null) {
        throw new IOException("String_Node_Str" + primeDocTerm.field() + "String_Node_Str");
      }
      TermsEnum termsEnum=terms.iterator(null);
      if (!termsEnum.seekExact(primeDocTerm.bytes(),true)) {
        throw new IOException("String_Node_Str" + primeDocTerm + "String_Node_Str");
      }
      DocsEnum docsEnum=termsEnum.docs(null,null);
      int docFreq=reader.docFreq(primeDocTerm);
      int doc;
      int count=0;
      while ((doc=docsEnum.nextDoc()) != DocIdSetIterator.NO_MORE_DOCS) {
        bs.fastSet(doc);
        count++;
      }
      if (count == docFreq) {
        primeDocMap.put(key,bs);
      }
 else {
        LOG.warn("String_Node_Str",reader,count,docFreq);
      }
      return bs;
    }
  }
  return bitSet;
}