From 21ee543edc0dea36ab58d24523fcd42b8a270df8 Mon Sep 17 00:00:00 2001
From: Michal Kubecek <mkubecek@suse.cz>
Date: Tue, 3 Jun 2014 10:26:06 +0200
Subject: [PATCH] xfrm: fix race between netns cleanup and state expire
 notification

The xfrm_user module registers its pernet init/exit after xfrm
itself so that its net exit function xfrm_user_net_exit() is
executed before xfrm_net_exit() which calls xfrm_state_fini() to
cleanup the SA's (xfrm states). This opens a window between
zeroing net->xfrm.nlsk pointer and deleting all xfrm_state
instances which may access it (via the timer). If an xfrm state
expires in this window, xfrm_exp_state_notify() will pass null
pointer as socket to nlmsg_multicast().

As the notifications are called inside rcu_read_lock() block, it
is sufficient to retrieve the nlsk socket with rcu_dereference()
and check the it for null.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Reading git-format-patch failed