From 6475a5bb3e718d87b0dc05bde99ca5bc7db5ec42 Mon Sep 17 00:00:00 2001
From: Lucas Clemente <lucas@clemente.io>
Date: Mon, 6 Jun 2016 23:36:48 +0200
Subject: [PATCH] fix a race condition in session.handleWindowUpdateFrame

---
 session.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/session.go b/session.go
index ec0e9c2f9..559f9aa06 100644
--- a/session.go
+++ b/session.go
@@ -336,6 +336,7 @@ func (s *Session) handleWindowUpdateFrame(frame *frames.WindowUpdateFrame) error
 		s.streamsMutex.RUnlock()
 	} else {
 		s.streamsMutex.RLock()
+		defer s.streamsMutex.RUnlock()
 		stream, streamExists := s.streams[frame.StreamID]
 		if !streamExists {
 			return errWindowUpdateOnInvalidStream
@@ -343,7 +344,6 @@ func (s *Session) handleWindowUpdateFrame(frame *frames.WindowUpdateFrame) error
 		if stream == nil {
 			return errWindowUpdateOnClosedStream
 		}
-		s.streamsMutex.RUnlock()
 
 		updated := stream.UpdateSendFlowControlWindow(frame.ByteOffset)
 		if updated {