diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 9624db80dc4e..d1c51b7f5221 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2209,12 +2209,8 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, goto out_unlock; } - /* - * We know this subsystem has not yet been bound. Users in a non-init - * user namespace may only mount hierarchies with no bound subsystems, - * i.e. 'none,name=user1' - */ - if (!opts.none && !capable(CAP_SYS_ADMIN)) { + /* Hierarchies may only be created in the initial cgroup namespace. */ + if (ns != &init_cgroup_ns) { ret = -EPERM; goto out_unlock; } @@ -2956,6 +2952,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) int retval = 0; mutex_lock(&cgroup_mutex); + percpu_down_write(&cgroup_threadgroup_rwsem); for_each_root(root) { struct cgroup *from_cgrp; @@ -2970,6 +2967,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) if (retval) break; } + percpu_up_write(&cgroup_threadgroup_rwsem); mutex_unlock(&cgroup_mutex); return retval; @@ -4337,6 +4335,8 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) mutex_lock(&cgroup_mutex); + percpu_down_write(&cgroup_threadgroup_rwsem); + /* all tasks in @from are being moved, all csets are source */ spin_lock_irq(&css_set_lock); list_for_each_entry(link, &from->cset_links, cset_link) @@ -4365,6 +4365,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) } while (task && !ret); out_err: cgroup_migrate_finish(&preloaded_csets); + percpu_up_write(&cgroup_threadgroup_rwsem); mutex_unlock(&cgroup_mutex); return ret; } @@ -6339,14 +6340,11 @@ struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, if (!ns_capable(user_ns, CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); - mutex_lock(&cgroup_mutex); + /* It is not safe to take cgroup_mutex here */ spin_lock_irq(&css_set_lock); - cset = task_css_set(current); get_css_set(cset); - spin_unlock_irq(&css_set_lock); - mutex_unlock(&cgroup_mutex); new_ns = alloc_cgroup_ns(); if (IS_ERR(new_ns)) { |