From 2ed35ac44d08fb50259b1e2a97da23b2be02c6c0 Mon Sep 17 00:00:00 2001
From: xtaci <daniel820313@gmail.com>
Date: Thu, 7 Nov 2019 13:30:11 +0800
Subject: [PATCH] fix race and parityshard leaks

---
 fec.go  | 2 +-
 sess.go | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fec.go b/fec.go
index ff81a7e2..97cd40b7 100644
--- a/fec.go
+++ b/fec.go
@@ -156,7 +156,7 @@ func (dec *fecDecoder) decode(in fecPacket) (recovered [][]byte) {
 					dlen := len(shards[k])
 					shards[k] = shards[k][:maxlen]
 					copy(shards[k][dlen:], dec.zeros)
-				} else {
+				} else if k < dec.dataShards {
 					shards[k] = xmitBuf.Get().([]byte)[:0]
 				}
 			}
diff --git a/sess.go b/sess.go
index 07a5e600..13a1a5c4 100644
--- a/sess.go
+++ b/sess.go
@@ -663,9 +663,10 @@ func (s *UDPSession) kcpInput(data []byte) {
 				if f.flag() == typeParity {
 					fecParityShards++
 				}
-				recovers := s.fecDecoder.decode(f)
 
+				// lock
 				s.mu.Lock()
+				recovers := s.fecDecoder.decode(f)
 				if f.flag() == typeData {
 					if ret := s.kcp.Input(data[fecHeaderSizePlus2:], true, s.ackNoDelay); ret != 0 {
 						kcpInErrors++