On Fri, May 27, 2016 at 05:31:24PM +0200, Michal Hocko wrote:
> On Thu 26-05-16 14:02:02, Andrew Morton wrote:
> > On Thu, 26 May 2016 16:30:18 -0400 Tejun Heo <tj@xxxxxxxxxx> wrote:
> >
> > > memcg_offline_kmem() may be called from memcg_free_kmem() after a css
> > > init failure. memcg_free_kmem() is a ->css_free callback which is
> > > called without cgroup_mutex and memcg_offline_kmem() ends up using
> > > css_for_each_descendant_pre() without any locking. Fix it by adding
> > > rcu read locking around it.
> > >
> > > mkdir: cannot create directory ___65530___: No space left on device
> > > [ 527.241361] ===============================
> > > [ 527.241845] [ INFO: suspicious RCU usage. ]
> > > [ 527.242367] 4.6.0-work+ #321 Not tainted
> > > [ 527.242730] -------------------------------
> > > [ 527.243220] kernel/cgroup.c:4008 cgroup_mutex or RCU read lock required!
> >
> > cc:stable?
>
> Also which kernel versions would be affected? I have tried to look and
> got lost in the indirection of the css_free path.
I think it's actually from 0b8f73e10428 ("mm: memcontrol: clean up
alloc, online, offline, free functions") which got merged during this
cycle, so no need for -stable.
Thanks.
--
tejun
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