1 files changed, 23 insertions, 1 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 71a58f67f481..d9ebebe1a2aa 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -313,12 +313,34 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
                 } else if (!locked)
                         spin_lock_irq(&zone->lru_lock);
 
+                /*
+                 * migrate_pfn does not necessarily start aligned to a
+                 * pageblock. Ensure that pfn_valid is called when moving
+                 * into a new MAX_ORDER_NR_PAGES range in case of large
+                 * memory holes within the zone
+                 */
+                if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
+                        if (!pfn_valid(low_pfn)) {
+                                low_pfn += MAX_ORDER_NR_PAGES - 1;
+                                continue;
+                        }
+                }
+
                 if (!pfn_valid_within(low_pfn))
                         continue;
                 nr_scanned++;
 
-                /* Get the page and skip if free */
+                /*
+                 * Get the page and ensure the page is within the same zone.
+                 * See the comment in isolate_freepages about overlapping
+                 * nodes. It is deliberate that the new zone lock is not taken
+                 * as memory compaction should not move pages between nodes.
+                 */
                 page = pfn_to_page(low_pfn);
+                if (page_zone(page) != zone)
+                        continue;
+
+                /* Skip if free */
                 if (PageBuddy(page))
                         continue;