diff --git a/buffer/src/main/java/io/netty/buffer/PoolArena.java b/buffer/src/main/java/io/netty/buffer/PoolArena.java
index 0a3f9f429e..6acd979665 100644
--- a/buffer/src/main/java/io/netty/buffer/PoolArena.java
+++ b/buffer/src/main/java/io/netty/buffer/PoolArena.java
@@ -151,11 +151,13 @@ abstract class PoolArena<T> {
         buf.initUnpooled(newUnpooledChunk(reqCapacity), reqCapacity);
     }
 
-    synchronized void free(PoolChunk<T> chunk, long handle) {
+     void free(PoolChunk<T> chunk, long handle) {
         if (chunk.unpooled) {
             destroyChunk(chunk);
         } else {
-            chunk.parent.free(chunk, handle);
+            synchronized(this) {
+                chunk.parent.free(chunk, handle);
+            }
         }
     }