rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt()

[pandora-kernel.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 850009a..2b8ba3a 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3377,9 +3377,15 @@ static void setup_zone_migrate_reserve(struct zone *zone)
        unsigned long block_migratetype;
        int reserve;
 
-       /* Get the start pfn, end pfn and the number of blocks to reserve */
+       /*
+        * Get the start pfn, end pfn and the number of blocks to reserve
+        * We have to be careful to be aligned to pageblock_nr_pages to
+        * make sure that we always check pfn_valid for the first page in
+        * the block.
+        */
        start_pfn = zone->zone_start_pfn;
        end_pfn = start_pfn + zone->spanned_pages;
+       start_pfn = roundup(start_pfn, pageblock_nr_pages);
        reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
                                                        pageblock_order;