mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-14 06:35:12 +00:00
Code Issues Releases Wiki Activity

cgroup: fix locking in cgroupstats_build()

Browse source 
css_set_lock has been converted to css_set_rwsem, and rwsem can't nest
inside rcu_read_lock.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2014-02-14 16:54:28 +08:00 committed by Tejun Heo
parent 430af8ad9d
commit bad3466034
1 changed files with 6 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
kernel/cgroup.c
View file

@ -2995,6 +2995,8 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
kernfs_type(kn) != KERNFS_DIR) kernfs_type(kn) != KERNFS_DIR)
return -EINVAL; return -EINVAL;
mutex_lock(&cgroup_mutex);
/* /*
* We aren't being called from kernfs and there's no guarantee on * We aren't being called from kernfs and there's no guarantee on
* @kn->priv's validity. For this and css_tryget_from_dir(), * @kn->priv's validity. For this and css_tryget_from_dir(),
@ -3002,10 +3004,12 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
*/ */
rcu_read_lock(); rcu_read_lock();
cgrp = rcu_dereference(kn->priv); cgrp = rcu_dereference(kn->priv);
if (!cgrp) { if (!cgrp || cgroup_is_dead(cgrp)) {
rcu_read_unlock(); rcu_read_unlock();
mutex_unlock(&cgroup_mutex);
return -ENOENT; return -ENOENT;
} }
rcu_read_unlock();
css_task_iter_start(&cgrp->dummy_css, &it); css_task_iter_start(&cgrp->dummy_css, &it);
while ((tsk = css_task_iter_next(&it))) { while ((tsk = css_task_iter_next(&it))) {
@ -3030,7 +3034,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
} }
css_task_iter_end(&it); css_task_iter_end(&it);
rcu_read_unlock(); mutex_unlock(&cgroup_mutex);
return 0; return 0;
} }