Date: Wed, 8 Jun 2011 14:09:51 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Igor Mammedov <imammedo@redhat.com>,
        Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>,
        Michal Hocko <mhocko@suse.cz>, linux-kernel@vger.kernel.org,
        balbir@linux.vnet.ibm.com, linux-mm@kvack.org,
        Paul Menage <menage@google.com>, Li Zefan <lizf@cn.fujitsu.com>,
        containers@lists.linux-foundation.org
Subject: Re: [PATCH] memcg: do not expose uninitialized mem_cgroup_per_node
 to world
Message-Id: <20110608140951.115ab1dd.akpm@linux-foundation.org>
In-Reply-To: <20110608123527.479e6991.kamezawa.hiroyu@jp.fujitsu.com>
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The original patch:

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4707,7 +4707,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 	if (!pn)
 		return 1;
 
-	mem->info.nodeinfo[node] = pn;
 	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
 		mz = &pn->zoneinfo[zone];
 		for_each_lru(l)
@@ -4716,6 +4715,7 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 		mz->on_tree = false;
 		mz->mem = mem;
 	}
+	mem->info.nodeinfo[node] = pn;
 	return 0;
 }

looks like a really good idea.  But it needs a new changelog and I'd be
a bit reluctant to merge it as it appears that the aptch removes our
only known way of reproducing a bug.

So for now I think I'll queue the patch up unchangelogged so the issue
doesn't get forgotten about.

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