From ba6b0979e346fd91d3b7ef6956d7155877308f0f Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Date: Thu, 19 May 2016 17:12:16 -0700
Subject: power: add zone range overlapping check

There is a system thats node's pfns are overlapped as follows:

  -----pfn-------->
  N0 N1 N2 N0 N1 N2

Therefore, we need to care this overlapping when iterating pfn range.

mark_free_pages() iterates requested zone's pfn range and unset all
range's bitmap first.  And then it marks freepages in a zone to the
bitmap.  If there is an overlapping zone, above unset could clear
previous marked bit and reference to this bitmap in the future will
cause the problem.  To prevent it, this patch adds a zone check in
mark_free_pages().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 19fe7e9..e132705 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2156,6 +2156,10 @@ void mark_free_pages(struct zone *zone)
 	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
 		if (pfn_valid(pfn)) {
 			page = pfn_to_page(pfn);
+
+			if (page_zone(page) != zone)
+				continue;
+
 			if (!swsusp_page_is_forbidden(page))
 				swsusp_unset_page_free(page);
 		}
-- 
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