Sorry for a late response. On Fri 27-05-16 11:51:40, Tejun Heo wrote: > 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. yes you are right! memcg_free_kmem didn't call memcg_offline_kmem before that commit. Thanks for the clarification. Anyway $ git describe --contains 0b8f73e10428 v4.5-rc1~30^2~11 So it would be stable # 4.5+ -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>