Date: Thu, 3 Oct 2013 13:42:04 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Zhang Yanfei <zhangyanfei.yes@gmail.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>, Tang Chen <tangchen@cn.fujitsu.com>,
        Toshi Kani <toshi.kani@hp.com>, isimatu.yasuaki@jp.fujitsu.com,
        Linux MM <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
        Wanpeng Li <liwanp@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/2] mm/sparsemem: Fix a bug in free_map_bootmem when
 CONFIG_SPARSEMEM_VMEMMAP
Message-Id: <20131003134204.e408977b42cb85984473cfd6@linux-foundation.org>
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	<524CE532.1030001@gmail.com>
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On Thu, 03 Oct 2013 11:32:02 +0800 Zhang Yanfei <zhangyanfei.yes@gmail.com> wrote:

> We pass the number of pages which hold page structs of a memory
> section to function free_map_bootmem. This is right when
> !CONFIG_SPARSEMEM_VMEMMAP but wrong when CONFIG_SPARSEMEM_VMEMMAP.
> When CONFIG_SPARSEMEM_VMEMMAP, we should pass the number of pages
> of a memory section to free_map_bootmem.
> 
> So the fix is removing the nr_pages parameter. When
> CONFIG_SPARSEMEM_VMEMMAP, we directly use the prefined marco
> PAGES_PER_SECTION in free_map_bootmem. When !CONFIG_SPARSEMEM_VMEMMAP,
> we calculate page numbers needed to hold the page structs for a
> memory section and use the value in free_map_bootmem.

What were the runtime user-visible effects of that bug?

Please always include this information when fixing a bug.
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