diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c194f9e4fc7b..f22e3cd1978b 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3927,6 +3927,18 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, if (!cgrp) return -ENOMEM; + /* + * Only live parents can have children. Note that the liveliness + * check isn't strictly necessary because cgroup_mkdir() and + * cgroup_rmdir() are fully synchronized by i_mutex; however, do it + * anyway so that locking is contained inside cgroup proper and we + * don't get nasty surprises if we ever grow another caller. + */ + if (!cgroup_lock_live_group(parent)) { + err = -ENODEV; + goto err_free; + } + /* Grab a reference on the superblock so the hierarchy doesn't * get deleted on unmount if there are child cgroups. This * can be done outside cgroup_mutex, since the sb can't @@ -3934,8 +3946,6 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, * fs */ atomic_inc(&sb->s_active); - mutex_lock(&cgroup_mutex); - init_cgroup_housekeeping(cgrp); cgrp->parent = parent; @@ -4006,7 +4016,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, /* Release the reference count that we took on the superblock */ deactivate_super(sb); - +err_free: kfree(cgrp); return err; } |