From 8f633fe363ae20d244e23b77b8dc5260b3171e8f Mon Sep 17 00:00:00 2001
From: fatedier <fatedier@gmail.com>
Date: Fri, 6 Mar 2026 15:55:22 +0800
Subject: [PATCH] fix: return buffers to pool on error paths to reduce GC
 pressure (#5203)

- pkg/nathole/nathole.go: add pool.PutBuf(buf) on ReadFromUDP error
  and DecodeMessageInto error paths in waitDetectMessage
- pkg/proto/udp/udp.go: add defer pool.PutBuf(buf) in writerFn to
  ensure buffer is returned when the goroutine exits
---
 pkg/nathole/nathole.go | 2 ++
 pkg/proto/udp/udp.go   | 1 +
 2 files changed, 3 insertions(+)

diff --git a/pkg/nathole/nathole.go b/pkg/nathole/nathole.go
index 72522fac..7d6ebe89 100644
--- a/pkg/nathole/nathole.go
+++ b/pkg/nathole/nathole.go
@@ -298,11 +298,13 @@ func waitDetectMessage(
 		n, raddr, err := conn.ReadFromUDP(buf)
 		_ = conn.SetReadDeadline(time.Time{})
 		if err != nil {
+			pool.PutBuf(buf)
 			return nil, err
 		}
 		xl.Debugf("get udp message local %s, from %s", conn.LocalAddr(), raddr)
 		var m msg.NatHoleSid
 		if err := DecodeMessageInto(buf[:n], key, &m); err != nil {
+			pool.PutBuf(buf)
 			xl.Warnf("decode sid message error: %v", err)
 			continue
 		}
diff --git a/pkg/proto/udp/udp.go b/pkg/proto/udp/udp.go
index 4d3df5af..21c41680 100644
--- a/pkg/proto/udp/udp.go
+++ b/pkg/proto/udp/udp.go
@@ -85,6 +85,7 @@ func Forwarder(dstAddr *net.UDPAddr, readCh <-chan *msg.UDPPacket, sendCh chan<-
 		}()
 
 		buf := pool.GetBuf(bufSize)
+		defer pool.PutBuf(buf)
 		for {
 			_ = udpConn.SetReadDeadline(time.Now().Add(30 * time.Second))
 			n, _, err := udpConn.ReadFromUDP(buf)