[PR #5203] [MERGED] fix: return buffers to pool on error paths to reduce GC pressure #5170

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opened 2026-05-05 14:56:02 -06:00 by gitea-mirror · 0 comments

gitea-mirror commented

2026-05-05 14:56:02 -06:00

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📋 Pull Request Information

Original PR: https://github.com/fatedier/frp/pull/5203
Author: @fatedier
Created: 3/6/2026
Status: ✅ Merged
Merged: 3/6/2026
Merged by: @fatedier

Base: dev ← Head: new

📝 Commits (1)

521724b fix: return buffers to pool on error paths to reduce GC pressure

📊 Changes

2 files changed (+3 additions, -0 deletions)

View changed files

📝 pkg/nathole/nathole.go (+2 -0)
📝 pkg/proto/udp/udp.go (+1 -0)

📄 Description

Summary

pkg/nathole/nathole.go: waitDetectMessage allocates a buffer via pool.GetBuf each loop iteration but never returns it on error paths (ReadFromUDP failure and DecodeMessageInto failure). Added pool.PutBuf(buf) on both paths.
pkg/proto/udp/udp.go: writerFn in Forwarder allocates a buffer via pool.GetBuf but never returns it when the goroutine exits. Added defer pool.PutBuf(buf).

These are sync.Pool buffer leaks — not permanent memory leaks, but they increase GC pressure and allocation rate under sustained load.

Verification

json.Unmarshal creates independent string copies, so returning buf to pool after DecodeMessageInto is safe (no aliasing).
NewUDPPacket copies buf[:n] into a new slice, so returning buf via defer in writerFn is safe.
No double-free paths exist in either fix.
Build and unit tests pass.

Test plan

make build passes
make test passes
Manual code review confirmed no aliasing or double-free issues
Codex deep analysis confirmed safety of both fixes

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/fatedier/frp/pull/5203 **Author:** [@fatedier](https://github.com/fatedier) **Created:** 3/6/2026 **Status:** ✅ Merged **Merged:** 3/6/2026 **Merged by:** [@fatedier](https://github.com/fatedier) **Base:** `dev` ← **Head:** `new` --- ### 📝 Commits (1) - [`521724b`](https://github.com/fatedier/frp/commit/521724bab382eec61961ac092d294b7d8ed98a42) fix: return buffers to pool on error paths to reduce GC pressure ### 📊 Changes **2 files changed** (+3 additions, -0 deletions) <details> <summary>View changed files</summary> 📝 `pkg/nathole/nathole.go` (+2 -0) 📝 `pkg/proto/udp/udp.go` (+1 -0) </details> ### 📄 Description ## Summary - **pkg/nathole/nathole.go**: `waitDetectMessage` allocates a buffer via `pool.GetBuf` each loop iteration but never returns it on error paths (`ReadFromUDP` failure and `DecodeMessageInto` failure). Added `pool.PutBuf(buf)` on both paths. - **pkg/proto/udp/udp.go**: `writerFn` in `Forwarder` allocates a buffer via `pool.GetBuf` but never returns it when the goroutine exits. Added `defer pool.PutBuf(buf)`. These are `sync.Pool` buffer leaks — not permanent memory leaks, but they increase GC pressure and allocation rate under sustained load. ## Verification - `json.Unmarshal` creates independent string copies, so returning `buf` to pool after `DecodeMessageInto` is safe (no aliasing). - `NewUDPPacket` copies `buf[:n]` into a new slice, so returning `buf` via defer in `writerFn` is safe. - No double-free paths exist in either fix. - Build and unit tests pass. ## Test plan - [x] `make build` passes - [x] `make test` passes - [x] Manual code review confirmed no aliasing or double-free issues - [x] Codex deep analysis confirmed safety of both fixes --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>