Messages in this thread | | | Date | Wed, 14 Nov 2012 11:04:07 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH 04/17] cgroup: create directory before linking while creating a new cgroup |
| |
Hello, Li.
On Wed, Nov 14, 2012 at 11:20:47AM +0800, Li Zefan wrote: > > It also removes the need to check whether cgroup->dentry is %NULL in > > cgroup_path. If a cgroup is visible, its dentry is guaranteed to be > > visible too. > > I'm afraid this isn't safe. > > The cgroup is visible to a controller soon after ss->create(), and then > the controller might call cgroup_path() while cgrp->dentry is still NULL.
Hmmm... I can't find any case where ss->create() is calling cgroup_path(). Do you remember which one that was?
> This can happen for cpu cgroup I think, and in fact the NULL check was > added for this reason IIRC.
Then, I think we better move the dentry assignment further up. It's really silly to be unable to answer "what's this new cgroup's name?" for any callback really. Will update accordingly.
Thanks.
-- tejun
| |