Re: [PATCH] cgroup: fix top cgroup refcnt leak

[Tejun Heo]

On Fri, Feb 14, 2014 at 07:15:18PM +0800, Li Zefan wrote:
> >  		/*
> > +		 * A root's lifetime is governed by its top cgroup.  Zero
> > +		 * ref indicate that the root is being destroyed.  Wait for
> > +		 * destruction to complete so that the subsystems are free.
> > +		 * We can use wait_queue for the wait but this path is
> > +		 * super cold.  Let's just sleep for a bit and retry.
> > +		 */
> > +		if (!atomic_read(&root->top_cgroup.refcnt)) {
> 
> oops, this fix is wrong. We call kernfs_mount() without cgroup locks and it
> drops cgroup refcnt if failed.
> 
> I guess we need to bump the refcnt and then drop it after kernfs_mount().

Alright, will wait for the updated fix.

Thanks!

-- 
tejun
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