Index: lucene/CHANGES.txt
===================================================================
--- lucene/CHANGES.txt	(revision 1368630)
+++ lucene/CHANGES.txt	(working copy)
@@ -13,6 +13,10 @@
 * LUCENE-2686, LUCENE-3505: Fix BooleanQuery scorers to return correct freq().
   (Koji Sekiguchi, Mike McCandless, Robert Muir)
 
+* LUCENE-2501: Fixed rare thread-safety issue that could cause
+  ArrayIndexOutOfBoundsException inside ByteBlockPool (Robert Muir,
+  Mike McCandless)
+
 ======================= Lucene 3.6.1 =======================
 More information about this release, including any errata related to the 
 release notes, upgrade instructions, or other changes may be found online at:
Index: lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java	(revision 1368630)
+++ lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java	(working copy)
@@ -48,7 +48,7 @@
 
   @Override
   int getStreamCount() {
-    if (fieldInfo.indexOptions != IndexOptions.DOCS_AND_FREQS_AND_POSITIONS)
+    if (indexOptions != IndexOptions.DOCS_AND_FREQS_AND_POSITIONS)
       return 1;
     else
       return 2;