--- zzzz-none-000/linux-3.10.107/include/linux/nsproxy.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/linux/nsproxy.h	2021-02-04 17:41:59.000000000 +0000
@@ -14,6 +14,10 @@
  * A structure to contain pointers to all per-process
  * namespaces - fs (mount), uts, network, sysvipc, etc.
  *
+ * The pid namespace is an exception -- it's accessed using
+ * task_active_pid_ns.  The pid namespace here is the
+ * namespace that children will use.
+ *
  * 'count' is the number of tasks holding a reference.
  * The count for each namespace, then, will be the number
  * of nsproxies pointing to it, not the number of tasks.
@@ -27,7 +31,7 @@
 	struct uts_namespace *uts_ns;
 	struct ipc_namespace *ipc_ns;
 	struct mnt_namespace *mnt_ns;
-	struct pid_namespace *pid_ns;
+	struct pid_namespace *pid_ns_for_children;
 	struct net 	     *net_ns;
 };
 extern struct nsproxy init_nsproxy;
@@ -36,32 +40,28 @@
  * the namespaces access rules are:
  *
  *  1. only current task is allowed to change tsk->nsproxy pointer or
- *     any pointer on the nsproxy itself
+ *     any pointer on the nsproxy itself.  Current must hold the task_lock
+ *     when changing tsk->nsproxy.
  *
  *  2. when accessing (i.e. reading) current task's namespaces - no
  *     precautions should be taken - just dereference the pointers
  *
  *  3. the access to other task namespaces is performed like this
- *     rcu_read_lock();
- *     nsproxy = task_nsproxy(tsk);
+ *     task_lock(task);
+ *     nsproxy = task->nsproxy;
  *     if (nsproxy != NULL) {
  *             / *
  *               * work with the namespaces here
  *               * e.g. get the reference on one of them
  *               * /
  *     } / *
- *         * NULL task_nsproxy() means that this task is
+ *         * NULL task->nsproxy means that this task is
  *         * almost dead (zombie)
  *         * /
- *     rcu_read_unlock();
+ *     task_unlock(task);
  *
  */
 
-static inline struct nsproxy *task_nsproxy(struct task_struct *tsk)
-{
-	return rcu_dereference(tsk->nsproxy);
-}
-
 int copy_namespaces(unsigned long flags, struct task_struct *tsk);
 void exit_task_namespaces(struct task_struct *tsk);
 void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);