Merge pull request #846 from hallyn/2016-02-24/cgns.auto

doc/lxc.container.conf.sgml.in

@@ -912,7 +912,7 @@ proc proc proc nodev,noexec,nosuid 0 0
                   the container's own cgroup into that directory.
                   The container will be able to write to its own
                   cgroup directory, but not the parents, since they
-                  will be remounted read-only
+                  will be remounted read-only.
                 </para>
               </listitem>
               <listitem>
@@ -987,6 +987,12 @@ proc proc proc nodev,noexec,nosuid 0 0
               </listitem>
             </itemizedlist>
             <para>
+	      If cgroup namespaces are enabled, then any <option>cgroup</option>
+	      auto-mounting request will be ignored, since the container can
+	      mount the filesystems itself, and automounting can confuse the
+	      container init.
+            </para>
+            <para>
               Note that if automatic mounting of the cgroup filesystem
               is enabled, the tmpfs under
               <filename>/sys/fs/cgroup</filename> will always be

src/lxc/cgfs.c

@@ -1356,6 +1356,9 @@ static bool cgroupfs_mount_cgroup(void *hdata, const char *root, int type)
 	struct cgroup_process_info *info, *base_info;
 	int r, saved_errno = 0;
 
+	if (cgns_supported())
+		return true;
+
 	cgfs_d = hdata;
 	if (!cgfs_d)
 		return false;