On 2014/2/12 0:26, Michal Hocko wrote: > On Tue 11-02-14 10:41:05, Tejun Heo wrote: > [...] >> @@ -4254,12 +4256,12 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, >> >> return 0; >> >> -err_unlock: >> - mutex_unlock(&cgroup_mutex); >> - /* Release the reference count that we took on the superblock */ >> - deactivate_super(sb); >> err_free_id: >> idr_remove(&root->cgroup_idr, cgrp->id); >> + /* Release the reference count that we took on the superblock */ >> + deactivate_super(sb); >> +err_unlock: >> + mutex_unlock(&cgroup_mutex); >> err_free_name: >> kfree(rcu_dereference_raw(cgrp->name)); >> err_free_cgrp: > > Do I have to change deactivate_super vs. mutex_unlock ordering in my > backport for 3.12 as well? > Your change is wrong that you shouldn't drop sb refcnt in err_unlock path. But you made me think if it's OK to hold cgroup_mutex while calling deactivate_super(), and the answer is NO! deactive_super() may call cgroup_kill_sb() which will acquire cgroup_mutex. I'll update the patch. Thank Tejun we won't be entangled with vfs internal anymore after coverting to kernfs. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
