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Subject: Re: mmotm woes, mainly compaction
References: <alpine.LSU.2.11.1604120005350.1832@eggly.anvils>
From: Vlastimil Babka <vbabka@suse.cz>
Message-ID: <570CABE3.4070404@suse.cz>
Date: Tue, 12 Apr 2016 10:03:47 +0200
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Sender: owner-linux-mm@kvack.org
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To: Hugh Dickins <hughd@google.com>, Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, Michal Hocko <mhocko@suse.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On 04/12/2016 09:18 AM, Hugh Dickins wrote:
> 2. Fix crash in get_pfnblock_flags_mask() from suitable_migration_target()
>     from isolate_freepages(): there's a case when that "block_start_pfn -=
>     pageblock_nr_pages" loop can pass through 0 and end up trying to access
>     a pageblock before the start of the mem_map[].  (I have not worked out
>     why this never hit me before 4.6-rc2-mm1, it looks much older.)

This is actually my fresh mmotm bug, thanks for catching that!

Fix for:
mm-compaction-wrap-calculating-first-and-last-pfn-of-pageblock.patch

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