Re: possible circular locking dependency mmap_sem/cpu_hotplug_lock.rw_sem

From: Artem Savkov
Date: Thu Aug 31 2017 - 08:19:45 EST


On Thu, Aug 31, 2017 at 02:09:51PM +0200, Michal Hocko wrote:
> On Thu 31-08-17 13:10:06, Artem Savkov wrote:
> > Hi Michal,
> >
> > On Wed, Aug 30, 2017 at 05:43:15PM +0200, Michal Hocko wrote:
> > > The previous patch is insufficient. drain_all_stock can still race with
> > > the memory offline callback and the underlying memcg disappear. So we
> > > need to be more careful and pin the css on the memcg. This patch
> > > instead...
> >
> > Tried this on top of rc7 and it does fix the splat for me.
>
> Thanks for testing! Can I assume your Tested-by?

Didn't test much more than the case that was causing it, but yes.

Reported-and-tested-by: Artem Savkov <asavkov@xxxxxxxxxx>

--
Regards,
Artem