1 files changed, 20 insertions, 0 deletions

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 16b20e38c4a1..b3c7fd554250 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -184,11 +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;