[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1349374157-20604-2-git-send-email-hannes@cmpxchg.org>
Date: Thu, 4 Oct 2012 14:09:16 -0400
From: Johannes Weiner <hannes@...xchg.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Michal Hocko <mhocko@...e.cz>,
Konstantin Khlebnikov <khlebnikov@...nvz.org>,
linux-mm@...ck.org, cgroups@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [patch 1/2] mm: memcontrol: handle potential crash when rmap races with task exit
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.
Signed-off-by: Johannes Weiner <hannes@...xchg.org>
Cc: stable@...nel.org [3.5]
---
include/linux/memcontrol.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 8d9489f..8686294 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -91,7 +91,7 @@ int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference((mm)->owner));
- match = __mem_cgroup_same_or_subtree(cgroup, memcg);
+ match = memcg && __mem_cgroup_same_or_subtree(cgroup, memcg);
rcu_read_unlock();
return match;
}
--
1.7.11.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists