---

yaml
---
r: 357756
b: refs/heads/master
c: e11f0ae
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0bd14b4fd72afd5df41e9fd59f356740f22fceba
+refs/heads/master: e11f0ae388f227d7ad03953e19034dec55286650

trunk/Documentation/namespaces/resource-control.txt

@@ -0,0 +1,14 @@
+There are a lot of kinds of objects in the kernel that don't have
+individual limits or that have limits that are ineffective when a set
+of processes is allowed to switch user ids.  With user namespaces
+enabled in a kernel for people who don't trust their users or their
+users programs to play nice this problems becomes more acute.
+
+Therefore it is recommended that memory control groups be enabled in
+kernels that enable user namespaces, and it is further recommended
+that userspace configure memory control groups to limit how much
+memory user's they don't trust to play nice can use.
+
+Memory control groups can be configured by installing the libcgroup
+package present on most distros editing /etc/cgrules.conf,
+/etc/cgconfig.conf and setting up libpam-cgroup.

trunk/init/Kconfig

@@ -1035,6 +1035,13 @@ config USER_NS
 	help
 	  This allows containers, i.e. vservers, to use user namespaces
 	  to provide different user info for different servers.
+
+	  When user namespaces are enabled in the kernel it is
+	  recommended that the MEMCG and MEMCG_KMEM options also be
+	  enabled and that user-space use the memory control groups to
+	  limit the amount of memory a memory unprivileged users can
+	  use.
+
 	  If unsure, say N.
 
 config PID_NS