From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 10 Jul 2025 06:32:02 +0000 (+1000)
Subject: Fix benign race on webseed cancellation flag
X-Git-Tag: v1.59.0~39
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=855ebc24276fe012ac65b4d1cfa892d6d51d016f;p=btrtrc.git

Fix benign race on webseed cancellation flag
---

diff --git a/webseed-peer.go b/webseed-peer.go
index 45b8c9be..80479e3b 100644
--- a/webseed-peer.go
+++ b/webseed-peer.go
@@ -135,7 +135,7 @@ func (ws *webseedPeer) runRequest(webseedRequest *webseedRequest) {
 	webseedRequest.Close()
 	if err != nil {
 		level := slog.LevelInfo
-		if webseedRequest.cancelled {
+		if webseedRequest.cancelled.Load() {
 			level = slog.LevelDebug
 		}
 		ws.slogger().Log(context.TODO(), level, "webseed request error", "err", err)
diff --git a/webseed-request.go b/webseed-request.go
index 51f76199..7e79f127 100644
--- a/webseed-request.go
+++ b/webseed-request.go
@@ -2,6 +2,7 @@ package torrent
 
 import (
 	"fmt"
+	"sync/atomic"
 
 	"github.com/anacrolix/torrent/webseed"
 )
@@ -16,7 +17,7 @@ type webseedRequest struct {
 	next RequestIndex
 	// One greater than the end of the range.
 	end       RequestIndex
-	cancelled bool
+	cancelled atomic.Bool
 }
 
 func (me *webseedRequest) Close() {
@@ -26,8 +27,7 @@ func (me *webseedRequest) Close() {
 // Record that it was exceptionally cancelled.
 func (me *webseedRequest) Cancel() {
 	me.request.Cancel()
-	if !me.cancelled {
-		me.cancelled = true
+	if !me.cancelled.Swap(true) {
 		if webseed.PrintDebug {
 			fmt.Printf("cancelled webseed request\n")
 		}