cgroup: lock cgroup_mutex in cgroup_init_subsys()
Make cgroup_init_subsys() grab cgroup_mutex while initializing a
subsystem so that all helpers and callbacks are called under the
context they expect. This isn't strictly necessary as
cgroup_init_subsys() doesn't race with anybody but will allow adding
lockdep assertions.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6cc693b..0975165 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4317,6 +4317,8 @@
printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
+ mutex_lock(&cgroup_mutex);
+
/* init base cftset */
cgroup_init_cftsets(ss);
@@ -4346,6 +4348,8 @@
if (ss->post_create)
ss->post_create(dummytop);
+ mutex_unlock(&cgroup_mutex);
+
/* this function shouldn't be used with modular subsystems, since they
* need to register a subsys_id, among other things */
BUG_ON(ss->module);