2 files changed, 8 insertions, 1 deletions

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index e2772666f004..7246ef3d4455 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -23,6 +23,7 @@ struct bsd_acct_struct;
 struct pid_namespace {
         struct kref kref;
         struct pidmap pidmap[PIDMAP_ENTRIES];
+        struct rcu_head rcu;
         int last_pid;
         unsigned int nr_hashed;
         struct task_struct *child_reaper;
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 42086551a24a..06c62de9c711 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -132,6 +132,12 @@ out:
         return ERR_PTR(err);
 }
 
+static void delayed_free_pidns(struct rcu_head *p)
+{
+        kmem_cache_free(pid_ns_cachep,
+                        container_of(p, struct pid_namespace, rcu));
+}
+
 static void destroy_pid_namespace(struct pid_namespace *ns)
 {
         int i;
@@ -140,7 +146,7 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
         for (i = 0; i < PIDMAP_ENTRIES; i++)
                 kfree(ns->pidmap[i].page);
         put_user_ns(ns->user_ns);
-        kmem_cache_free(pid_ns_cachep, ns);
+        call_rcu(&ns->rcu, delayed_free_pidns);
 }
 
 struct pid_namespace *copy_pid_ns(unsigned long flags,