Re: [PATCH 5/5] blk-cgroup: Fix an RCU warning in blkiocg_create()

Paul E. McKenney
2010-05-07T14:55:25Z

On Fri, May 07, 2010 at 08:57:41AM +0200, Jens Axboe wrote:
> On Fri, May 07 2010, Li Zefan wrote:
> > Paul E. McKenney wrote:
> > > On Thu, Apr 22, 2010 at 05:32:28PM +0800, Li Zefan wrote:
> > >> with CONFIG_PROVE_RCU=y, a warning can be triggered:
> > >>
> > >> # mount -t cgroup -o blkio xxx /mnt
> > >> # mkdir /mnt/subgroup
> > >>
> > >> ...
> > >> kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
> > >> ...
> > >>
> > >> To fix this, we avoid caling css_depth() here, which is a bit simpler
> > >> than the original code.
> > >
> > > Queued for 2.6.34, thank you!
> > >
> >
> > Seems neither you nor Jens queued this patch...
>
> I've included it now, thanks.

<red face> Thank you both for catching this one!!!

Thanx, Paul