On Thu, Oct 04, 2012 at 08:49:58PM +0200, Michal Hocko wrote:

On Thu 04-10-12 14:09:16, Johannes Weiner wrote:

quoted

page_referenced() counts only references of mm's that are associated
with the memcg hierarchy that is being reclaimed.  However, if it
races with the owner of the mm exiting, mm->owner may be NULL.  Don't
crash, just ignore the reference.

This seems to be fixed by Hugh's patch 3a981f48 "memcg: fix use_hierarchy
css_is_ancestor oops regression" which seems to be merged already.

And look who acked the patch.  I'll show myself out...