From 1a6f16b4c2c06060c65837c1167d055ec93bded5 Mon Sep 17 00:00:00 2001
From: abicky <takeshi.arabiki@gmail.com>
Date: Fri, 20 Oct 2017 18:34:42 +0900
Subject: [PATCH] Process chunks with buffer lock in enqueue_chunk

In flush threads @buffer could call destructive
methods of chunks in @queue without chunk lock,
so buffer lock is required.
---
 lib/fluent/plugin/buffer.rb | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/lib/fluent/plugin/buffer.rb b/lib/fluent/plugin/buffer.rb
index f62e92a713..337b3b79c8 100644
--- a/lib/fluent/plugin/buffer.rb
+++ b/lib/fluent/plugin/buffer.rb
@@ -319,21 +319,19 @@ def enqueue_chunk(metadata)
         return nil unless chunk
 
         chunk.synchronize do
-          if chunk.empty?
-            chunk.close
-          else
-            synchronize do
+          synchronize do
+            if chunk.empty?
+              chunk.close
+            else
               @queue << chunk
               @queued_num[metadata] = @queued_num.fetch(metadata, 0) + 1
+              chunk.enqueued!
             end
-            chunk.enqueued!
+            bytesize = chunk.bytesize
+            @stage_size -= bytesize
+            @queue_size += bytesize
           end
         end
-        bytesize = chunk.bytesize
-        synchronize do
-          @stage_size -= bytesize
-          @queue_size += bytesize
-        end
         nil
       end