memcg: mm_update_next_owner() should skip kthreads

"Search through everything else" in mm_update_next_owner() can hit a
kthread which adopted this "mm" via use_mm(), it should not be used as
mm->owner.  Add the PF_KTHREAD check.

While at it, change this code to use for_each_process_thread() instead
of deprecated do_each_thread/while_each_thread.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Peter Chiang <pchiang@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-06-04 16:07:52 -07:00 committed by Linus Torvalds
parent f7e2f7e896
commit f87fb599ae

View File

@ -395,14 +395,12 @@ retry:
} }
/* /*
* Search through everything else. We should not get * Search through everything else, we should not get here often.
* here often
*/ */
do_each_thread(g, c) { for_each_process_thread(g, c) {
if (c->mm == mm) if (!(c->flags & PF_KTHREAD) && c->mm == mm)
goto assign_new_owner; goto assign_new_owner;
} while_each_thread(g, c); }
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
/* /*
* We found no owner yet mm_users > 1: this implies that we are * We found no owner yet mm_users > 1: this implies that we are