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Date: Wed, 19 Feb 2014 15:32:37 -0800
From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: Michal Hocko <mhocko@suse.cz>, Mel Gorman <mgorman@suse.de>,
 linux-mm@kvack.org, Christoph Lameter <cl@linux.com>,
 David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
 Ben Herrenschmidt <benh@kernel.crashing.org>,
 Anton Blanchard <anton@samba.org>, linuxppc-dev@lists.ozlabs.org,
 akpm@linux-foundation.org
Subject: Re: [PATCH 1/3] mm: return NUMA_NO_NODE in local_memory_node if
 zonelists are not setup
Message-ID: <20140219233237.GF413@linux.vnet.ibm.com>
References: <20140219231641.GA413@linux.vnet.ibm.com>
 <20140219231714.GB413@linux.vnet.ibm.com>
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[ Grr, sorry for not including you originally Andrew, if this ends up
being ok with others, it will probably need to go through your tree. ]

On 19.02.2014 [15:17:14 -0800], Nishanth Aravamudan wrote:
> We can call local_memory_node() before the zonelists are setup. In that
> case, first_zones_zonelist() will not set zone and the reference to
> zone->node will Oops. Catch this case, and, since we presumably running
> very early, just return that any node will do.
> 
> Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.cz>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Christoph Lameter <cl@linux.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
> Cc: Anton Blanchard <anton@samba.org>
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index e3758a0..5de4337 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3650,6 +3650,8 @@ int local_memory_node(int node)
>  				   gfp_zone(GFP_KERNEL),
>  				   NULL,
>  				   &zone);
> +	if (!zone)
> +		return NUMA_NO_NODE;
>  	return zone->node;
>  }
>  #endif