From c31368fffb83f808ab3cbf503fcf1592fdde40a3 Mon Sep 17 00:00:00 2001
From: Rob Murray <rob.murray@docker.com>
Date: Fri, 11 Jul 2025 17:55:54 +0100
Subject: [PATCH] Don't raise an error when stopping a stopped docker-proxy

Signed-off-by: Rob Murray <rob.murray@docker.com>
---
 libnetwork/drivers/bridge/port_mapping_linux.go |  2 +-
 libnetwork/portmapper/proxy_linux.go            | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/libnetwork/drivers/bridge/port_mapping_linux.go b/libnetwork/drivers/bridge/port_mapping_linux.go
index eade34381c..c6fbd2ca07 100644
--- a/libnetwork/drivers/bridge/port_mapping_linux.go
+++ b/libnetwork/drivers/bridge/port_mapping_linux.go
@@ -799,7 +799,7 @@ func releasePortBindings(pbs []portBinding, fwn firewaller.Network) error {
 			}
 		}
 		if pb.stopProxy != nil {
-			if err := pb.stopProxy(); err != nil {
+			if err := pb.stopProxy(); err != nil && !errors.Is(err, os.ErrProcessDone) {
 				errs = append(errs, fmt.Errorf("failed to stop userland proxy for port mapping %s: %w", pb, err))
 			}
 		}
diff --git a/libnetwork/portmapper/proxy_linux.go b/libnetwork/portmapper/proxy_linux.go
index 1d84327802..0d9ffda702 100644
--- a/libnetwork/portmapper/proxy_linux.go
+++ b/libnetwork/portmapper/proxy_linux.go
@@ -1,6 +1,7 @@
 package portmapper
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -8,9 +9,11 @@ import (
 	"os/exec"
 	"runtime"
 	"strconv"
+	"sync/atomic"
 	"syscall"
 	"time"
 
+	"github.com/containerd/log"
 	"github.com/docker/docker/libnetwork/types"
 )
 
@@ -68,6 +71,7 @@ func StartProxy(pb types.PortBinding,
 	// proxy from getting terminated early. See https://go.dev/issue/27505
 	// for more details.
 	started := make(chan error)
+	var stopped atomic.Bool
 	go func() {
 		runtime.LockOSThread()
 		defer runtime.UnlockOSThread()
@@ -76,7 +80,17 @@ func StartProxy(pb types.PortBinding,
 		if err != nil {
 			return
 		}
-		wait <- cmd.Wait()
+		err = cmd.Wait()
+		if !stopped.Load() {
+			log.G(context.Background()).WithFields(log.Fields{
+				"proto":          pb.Proto,
+				"host-ip":        pb.HostIP,
+				"host-port":      pb.HostPort,
+				"container-ip":   pb.IP,
+				"container-port": pb.Port,
+			}).Info("Userland proxy exited early (this is expected during daemon shutdown)")
+		}
+		wait <- err
 	}()
 	if err := <-started; err != nil {
 		return nil, err
@@ -120,6 +134,7 @@ func StartProxy(pb types.PortBinding,
 		if cmd.Process == nil {
 			return nil
 		}
+		stopped.Store(true)
 		if err := cmd.Process.Signal(os.Interrupt); err != nil {
 			return err
 		}