From c7ba8287cd11f2fc9e2feee9e1fac34b7293658f Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Sat, 29 Jun 2013 14:06:10 -0700
Subject: [PATCH] cgroup: CGRP_ROOT_SUBSYS_BOUND should also be ignored when
mounting an existing hierarchy
0ce6cba357 ("cgroup: CGRP_ROOT_SUBSYS_BOUND should be ignored when
comparing mount options") only updated the remount path but
CGRP_ROOT_SUBSYS_BOUND should also be ignored when comparing options
while mounting an existing hierarchy. As option mismatch triggers a
warning but doesn't fail the mount without sane_behavior, this only
triggers a spurious warning message.
Fix it by only comparing CGRP_ROOT_OPTION_MASK bits when comparing new
and existing root options.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 5a2fcf5bcc4a..e5583d10a325 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1703,7 +1703,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
*/
cgroup_free_root(opts.new_root);
- if (root->flags != opts.flags) {
+ if ((root->flags ^ opts.flags) & CGRP_ROOT_OPTION_MASK) {
if ((root->flags | opts.flags) & CGRP_ROOT_SANE_BEHAVIOR) {
pr_err("cgroup: sane_behavior: new mount options should match the existing superblock\n");
ret = -EINVAL;