Messages in this thread Patch in this message |  | | Date | Fri, 14 Feb 2014 16:54:28 +0800 | From | Li Zefan <> | Subject | [PATCH 1/3] cgroup: fix locking in cgroupstats_build() |
| |
css_set_lock has been converted to css_set_rwsem, and rwsem can't nested inside rcu_read_lock.
Signed-off-by: Li Zefan <lizefan@huawei.com> --- kernel/cgroup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index af4ecc3..0e794ca 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2997,6 +2997,8 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) kernfs_type(kn) != KERNFS_DIR) return -EINVAL; + mutex_lock(&cgroup_mutex); + /* * We aren't being called from kernfs and there's no guarantee on * @kn->priv's validity. For this and css_tryget_from_dir(), @@ -3004,10 +3006,12 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) */ rcu_read_lock(); cgrp = rcu_dereference(kn->priv); - if (!cgrp) { + if (!cgrp || cgroup_is_dead(cgrp)) { rcu_read_unlock(); + mutex_unlock(&cgroup_mutex); return -ENOENT; } + rcu_read_unlock(); css_task_iter_start(&cgrp->dummy_css, &it); while ((tsk = css_task_iter_next(&it))) { @@ -3032,7 +3036,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) } css_task_iter_end(&it); - rcu_read_unlock(); + mutex_unlock(&cgroup_mutex); return 0; } -- 1.8.0.2
|  |