fix containerd WaitTimeout

`defer r.WaitTimeout(10s)` was in a wrong place and had caused the
daemon to hang for 10 seconds.

Fix #39025

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

cmd/dockerd/daemon.go

@@ -164,7 +164,11 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
-	if err := cli.initContainerD(ctx); err != nil {
+	waitForContainerDShutdown, err := cli.initContainerD(ctx)
+	if waitForContainerDShutdown != nil {
+		defer waitForContainerDShutdown(10 * time.Second)
+	}
+	if err != nil {
 		cancel()
 		return err
 	}

cmd/dockerd/daemon_unix.go

@@ -145,30 +145,31 @@ func newCgroupParent(config *config.Config) string {
 	return cgroupParent
 }
 
-func (cli *DaemonCli) initContainerD(ctx context.Context) error {
+func (cli *DaemonCli) initContainerD(ctx context.Context) (func(time.Duration) error, error) {
+	var waitForShutdown func(time.Duration) error
 	if cli.Config.ContainerdAddr == "" {
 		systemContainerdAddr, ok, err := systemContainerdRunning(cli.Config.IsRootless())
 		if err != nil {
-			return errors.Wrap(err, "could not determine whether the system containerd is running")
+			return nil, errors.Wrap(err, "could not determine whether the system containerd is running")
 		}
 		if !ok {
 			opts, err := cli.getContainerdDaemonOpts()
 			if err != nil {
-				return errors.Wrap(err, "failed to generate containerd options")
+				return nil, errors.Wrap(err, "failed to generate containerd options")
 			}
 
 			r, err := supervisor.Start(ctx, filepath.Join(cli.Config.Root, "containerd"), filepath.Join(cli.Config.ExecRoot, "containerd"), opts...)
 			if err != nil {
-				return errors.Wrap(err, "failed to start containerd")
+				return nil, errors.Wrap(err, "failed to start containerd")
 			}
 			cli.Config.ContainerdAddr = r.Address()
 
 			// Try to wait for containerd to shutdown
-			defer r.WaitTimeout(10 * time.Second)
+			waitForShutdown = r.WaitTimeout
 		} else {
 			cli.Config.ContainerdAddr = systemContainerdAddr
 		}
 	}
 
-	return nil
+	return waitForShutdown, nil
 }

cmd/dockerd/daemon_windows.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"time"
 
 	"github.com/docker/docker/daemon/config"
 	"github.com/docker/docker/libcontainerd/supervisor"
@@ -88,7 +89,7 @@ func newCgroupParent(config *config.Config) string {
 	return ""
 }
 
-func (cli *DaemonCli) initContainerD(_ context.Context) error {
+func (cli *DaemonCli) initContainerD(_ context.Context) (func(time.Duration) error, error) {
 	system.InitContainerdRuntime(cli.Config.Experimental, cli.Config.ContainerdAddr)
-	return nil
+	return nil, nil
 }