From mboxrd@z Thu Jan  1 00:00:00 1970
From: Igor Mammedov <imammedo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH] memcg: do not expose uninitialized mem_cgroup_per_node
	to world
Date: Fri, 10 Jun 2011 18:57:40 +0200
Message-ID: <4DF24D04.1080802__7973.64469985968$1307725134$gmane$org@redhat.com>
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To: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Tim Deegan <Tim.Deegan-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Hiroyuki Kamezawa <kamezawa.hiroyuki-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org
List-Id: containers.vger.kernel.org

On 06/08/2011 11:09 PM, Andrew Morton wrote:
> 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.
>
Problem was in rhel's xen hv.
It was missing fix for imul emulation.
Details here 
http://lists.xensource.com/archives/html/xen-devel/2011-06/msg00801.html
Thanks to Tim Deegan and everyone who was involved in the discussion.

-- 
Thanks,
  Igor