Re: mmotm woes, mainly compaction

From: Vlastimil Babka
Date: Tue Apr 12 2016 - 04:03:59 EST


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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