From 0ac3cd1be170d180b2baed755e8f0da547ceb267 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kenfe-Micka=C3=ABl=20Laventure?=
 <mickael.laventure@gmail.com>
Date: Fri, 15 Jul 2016 11:49:43 -0700
Subject: [PATCH] Fix shim deadlock when joining an existing pid namespace
 (#290)

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
---
 containerd-shim/main.go  |  1 +
 runtime/runtime_test.go  | 12 ++++++++----
 supervisor/delete.go     |  4 ++++
 supervisor/exit.go       |  8 +++++---
 supervisor/supervisor.go |  1 -
 supervisor/worker.go     |  3 +++
 6 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/containerd-shim/main.go b/containerd-shim/main.go
index ddfee9a..a865931 100644
--- a/containerd-shim/main.go
+++ b/containerd-shim/main.go
@@ -115,6 +115,7 @@ func start(log *os.File) error {
 			// runtime has exited so the shim can also exit
 			if exitShim {
 				// Let containerd take care of calling the runtime delete
+				f.Close()
 				p.Wait()
 				return nil
 			}
diff --git a/runtime/runtime_test.go b/runtime/runtime_test.go
index 7b737a5..3581493 100644
--- a/runtime/runtime_test.go
+++ b/runtime/runtime_test.go
@@ -1,6 +1,7 @@
 package runtime
 
 import (
+	"flag"
 	"fmt"
 	"io"
 	"os"
@@ -9,14 +10,13 @@ import (
 	"syscall"
 	"testing"
 	"time"
-	"flag"
 
 	utils "github.com/docker/containerd/testutils"
 )
 
 var (
-	devNull = "/dev/null"
-	stdin   io.WriteCloser
+	devNull     = "/dev/null"
+	stdin       io.WriteCloser
 	runtimeTool = flag.String("runtime", "runc", "Runtime to use for this test")
 )
 
@@ -163,13 +163,17 @@ func BenchmarkBusyboxSh(b *testing.B) {
 }
 
 func benchmarkStartContainer(b *testing.B, c Container, s Stdio, bundleName string) {
-	if _, err := c.Start("", s); err != nil {
+	p, err := c.Start("", s)
+	if err != nil {
 		b.Fatalf("Error starting container %v", err)
 	}
 
 	kill := exec.Command(c.Runtime(), "kill", bundleName, "KILL")
 	kill.Run()
 
+	p.Wait()
+	c.Delete()
+
 	// wait for kill to finish. selected wait time is arbitrary
 	time.Sleep(500 * time.Millisecond)
 
diff --git a/supervisor/delete.go b/supervisor/delete.go
index 931ad8c..95720d5 100644
--- a/supervisor/delete.go
+++ b/supervisor/delete.go
@@ -14,6 +14,7 @@ type DeleteTask struct {
 	Status  int
 	PID     string
 	NoEvent bool
+	Process runtime.Process
 }
 
 func (s *Supervisor) delete(t *DeleteTask) error {
@@ -22,6 +23,9 @@ func (s *Supervisor) delete(t *DeleteTask) error {
 		if err := s.deleteContainer(i.container); err != nil {
 			logrus.WithField("error", err).Error("containerd: deleting container")
 		}
+		if t.Process != nil {
+			t.Process.Wait()
+		}
 		if !t.NoEvent {
 			s.notifySubscribers(Event{
 				Type:      StateExit,
diff --git a/supervisor/exit.go b/supervisor/exit.go
index f96d925..442327d 100644
--- a/supervisor/exit.go
+++ b/supervisor/exit.go
@@ -46,9 +46,10 @@ func (s *Supervisor) exit(t *ExitTask) error {
 	}
 	container := proc.Container()
 	ne := &DeleteTask{
-		ID:     container.ID(),
-		Status: status,
-		PID:    proc.ID(),
+		ID:      container.ID(),
+		Status:  status,
+		PID:     proc.ID(),
+		Process: proc,
 	}
 	s.delete(ne)
 
@@ -72,6 +73,7 @@ func (s *Supervisor) execExit(t *ExecExitTask) error {
 	if err := container.RemoveProcess(t.PID); err != nil {
 		logrus.WithField("error", err).Error("containerd: find container for pid")
 	}
+	t.Process.Wait()
 	s.notifySubscribers(Event{
 		Timestamp: time.Now(),
 		ID:        t.ID,
diff --git a/supervisor/supervisor.go b/supervisor/supervisor.go
index d900bb0..9055ac0 100644
--- a/supervisor/supervisor.go
+++ b/supervisor/supervisor.go
@@ -282,7 +282,6 @@ func (s *Supervisor) SendTask(evt Task) {
 
 func (s *Supervisor) exitHandler() {
 	for p := range s.monitor.Exits() {
-		p.Wait()
 		e := &ExitTask{
 			Process: p,
 		}
diff --git a/supervisor/worker.go b/supervisor/worker.go
index e226c21..ac7735d 100644
--- a/supervisor/worker.go
+++ b/supervisor/worker.go
@@ -51,6 +51,7 @@ func (w *worker) Start() {
 			evt := &DeleteTask{
 				ID:      t.Container.ID(),
 				NoEvent: true,
+				Process: process,
 			}
 			w.s.SendTask(evt)
 			continue
@@ -66,6 +67,7 @@ func (w *worker) Start() {
 			evt := &DeleteTask{
 				ID:      t.Container.ID(),
 				NoEvent: true,
+				Process: process,
 			}
 			w.s.SendTask(evt)
 			continue
@@ -76,6 +78,7 @@ func (w *worker) Start() {
 			evt := &DeleteTask{
 				ID:      t.Container.ID(),
 				NoEvent: true,
+				Process: process,
 			}
 			w.s.SendTask(evt)
 			continue