PATCH userns: release the reference of user_ns when destroying a pid_ns

[Zhao Hongjiang <zhaohongjiang37-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Zhao Hongjiang <zhaohongjiang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

We should release the reference of user_ns which belong to the pid_ns when the
pid_ns's reference is down to zero, because when we create a new pid_ns we get the
reference of the user_ns.

Signed-off-by: Zhao Hongjiang <zhaohongjiang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
 kernel/pid_namespace.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 2d6010a..f303462 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -127,6 +127,7 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
 {
 	int i;

+	put_user_ns(ns->user_ns);
 	proc_free_inum(ns->proc_inum);
 	for (i = 0; i < PIDMAP_ENTRIES; i++)
 		kfree(ns->pidmap[i].page);
-- 1.7.1