fixed race

client-stats.go

@@ -40,7 +40,7 @@ type ClientStats struct {
 
 func (cl *Client) statsLocked() (stats ClientStats) {
 	stats.ConnStats = cl.connStats.Copy()
-	stats.ActiveHalfOpenAttempts = cl.numHalfOpen
+	stats.ActiveHalfOpenAttempts = int(cl.numHalfOpen.Load())
 
 	stats.NumPeersUndialableWithoutHolepunch = len(cl.undialableWithoutHolepunch)
 	stats.NumPeersUndialableWithoutHolepunchDialedAfterHolepunchConnect = len(cl.undialableWithoutHolepunchDialedAfterHolepunchConnect)

client.go

@@ -37,6 +37,8 @@ import (
 	gbtree "github.com/google/btree"
 	"github.com/pion/datachannel"
 
+	"sync/atomic"
+
 	"github.com/anacrolix/torrent/bencode"
 	"github.com/anacrolix/torrent/internal/check"
 	"github.com/anacrolix/torrent/internal/limiter"
@@ -84,7 +86,7 @@ type Client struct {
 	pieceRequestOrder map[interface{}]*request_strategy.PieceRequestOrder
 
 	acceptLimiter map[ipStr]int
-	numHalfOpen   int
+	numHalfOpen   atomic.Int64
 
 	websocketTrackers websocketTrackers
 
@@ -691,8 +693,8 @@ func (cl *Client) noLongerHalfOpen(t *Torrent, addr string, attemptKey outgoingC
 		panic("should exist")
 	}
 	path.Delete()
-	cl.numHalfOpen--
-	if cl.numHalfOpen < 0 {
+	cl.numHalfOpen.Store(cl.numHalfOpen.Load() - 1)
+	if cl.numHalfOpen.Load() < 0 {
 		panic("should not be possible")
 	}
 	for _, t := range cl.torrentsAsSlice() {

torrent.go

@@ -1734,7 +1734,7 @@ func (t *Torrent) openNewConns(lock bool) (initiated int) {
 		if len(t.cl.dialers) == 0 {
 			return
 		}
-		if t.cl.numHalfOpen >= t.cl.config.TotalHalfOpenConns {
+ 		if int(t.cl.numHalfOpen.Load()) >= t.cl.config.TotalHalfOpenConns {
 			return
 		}
 		p := t.peers.PopMax()
@@ -3108,7 +3108,7 @@ func (t *Torrent) addHalfOpen(addrStr string, attemptKey *PeerInfo, lock bool) {
 		panic("should be unique")
 	}
 	path.Set(attemptKey)
-	t.cl.numHalfOpen++
+	t.cl.numHalfOpen.Store(t.cl.numHalfOpen.Load() + 1)
 }
 
 // Start the process of connecting to the given peer for the given torrent if appropriate. I'm not