diff --git a/libcontainer/configs/namespaces_syscall.go b/libcontainer/configs/namespaces_syscall.go
index 0516dba8d..543e059aa 100644
--- a/libcontainer/configs/namespaces_syscall.go
+++ b/libcontainer/configs/namespaces_syscall.go
@@ -31,3 +31,15 @@ func (n *Namespaces) CloneFlags() uintptr {
 	}
 	return uintptr(flag)
 }
+
+// IsPrivate tells whether the namespace of type t is configured as private
+// (i.e. it exists and is not shared).
+func (n Namespaces) IsPrivate(t NamespaceType) bool {
+	for _, v := range n {
+		if v.Type == t {
+			return v.Path == ""
+		}
+	}
+	// Not found, so implicitly sharing a parent namespace.
+	return false
+}
diff --git a/libcontainer/container_linux.go b/libcontainer/container_linux.go
index 73264bc90..59262d3ab 100644
--- a/libcontainer/container_linux.go
+++ b/libcontainer/container_linux.go
@@ -549,7 +549,6 @@ func (c *Container) newInitProcess(p *Process, cmd *exec.Cmd, messageSockPair, l
 			nsMaps[ns.Type] = ns.Path
 		}
 	}
-	_, sharePidns := nsMaps[configs.NEWPID]
 	data, err := c.bootstrapData(c.config.Namespaces.CloneFlags(), nsMaps, initStandard)
 	if err != nil {
 		return nil, err
@@ -594,7 +593,7 @@ func (c *Container) newInitProcess(p *Process, cmd *exec.Cmd, messageSockPair, l
 		container:       c,
 		process:         p,
 		bootstrapData:   data,
-		sharePidns:      sharePidns,
+		sharePidns:      !c.config.Namespaces.IsPrivate(configs.NEWPID),
 	}
 	c.initProcess = init
 	return init, nil
diff --git a/libcontainer/integration/exec_test.go b/libcontainer/integration/exec_test.go
index 376dd0f1f..4ac0f466b 100644
--- a/libcontainer/integration/exec_test.go
+++ b/libcontainer/integration/exec_test.go
@@ -1355,16 +1355,26 @@ func TestPIDHost(t *testing.T) {
 	}
 }
 
-func TestPIDHostInitProcessWait(t *testing.T) {
+func TestHostPidnsInitKill(t *testing.T) {
+	config := newTemplateConfig(t, nil)
+	// Implicitly use host pid ns.
+	config.Namespaces.Remove(configs.NEWPID)
+	testPidnsInitKill(t, config)
+}
+
+func TestSharedPidnsInitKill(t *testing.T) {
+	config := newTemplateConfig(t, nil)
+	// Explicitly use host pid ns.
+	config.Namespaces.Add(configs.NEWPID, "/proc/1/ns/pid")
+	testPidnsInitKill(t, config)
+}
+
+func testPidnsInitKill(t *testing.T, config *configs.Config) {
 	if testing.Short() {
 		return
 	}
 
-	pidns := "/proc/1/ns/pid"
-
 	// Run a container with two long-running processes.
-	config := newTemplateConfig(t, nil)
-	config.Namespaces.Add(configs.NEWPID, pidns)
 	container, err := newContainer(t, config)
 	ok(t, err)
 	defer func() {