Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[karo-tx-linux.git] / kernel / pid_namespace.c

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 57bc1fd35b3cbe6bffdbfe71af5f13fc00648b81..b3c7fd5542500ab13940814211692bbe3b7ef8d3 100644 (file)
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -149,7 +149,12 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {
        int nr;
        int rc;
-       struct task_struct *task;
+       struct task_struct *task, *me = current;
+
+       /* Ignore SIGCHLD causing any terminated children to autoreap */
+       spin_lock_irq(&me->sighand->siglock);
+       me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN;
+       spin_unlock_irq(&me->sighand->siglock);
 
        /*
         * The last thread in the cgroup-init thread group is terminating.
@@ -179,11 +184,31 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
        }
        read_unlock(&tasklist_lock);
 
+       /* Firstly reap the EXIT_ZOMBIE children we may have. */
        do {
                clear_thread_flag(TIF_SIGPENDING);
                rc = sys_wait4(-1, NULL, __WALL, NULL);
        } while (rc != -ECHILD);
 
+       /*
+        * sys_wait4() above can't reap the TASK_DEAD children.
+        * Make sure they all go away, see __unhash_process().
+        */
+       for (;;) {
+               bool need_wait = false;
+
+               read_lock(&tasklist_lock);
+               if (!list_empty(&current->children)) {
+                       __set_current_state(TASK_UNINTERRUPTIBLE);
+                       need_wait = true;
+               }
+               read_unlock(&tasklist_lock);
+
+               if (!need_wait)
+                       break;
+               schedule();
+       }
+
        if (pid_ns->reboot)
                current->signal->group_exit_code = pid_ns->reboot;
 
@@ -191,6 +216,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
        return;
 }
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
 static int pid_ns_ctl_handler(struct ctl_table *table, int write,
                void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -218,8 +244,8 @@ static struct ctl_table pid_ns_ctl_table[] = {
        },
        { }
 };
-
 static struct ctl_path kern_path[] = { { .procname = "kernel", }, { } };
+#endif /* CONFIG_CHECKPOINT_RESTORE */
 
 int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
 {
@@ -253,7 +279,10 @@ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
 static __init int pid_namespaces_init(void)
 {
        pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
        register_sysctl_paths(kern_path, pid_ns_ctl_table);
+#endif
        return 0;
 }