[PATCH] mm/cma: fix race

[Joonsoo Kim]

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
 mm/page_alloc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c6c38ed..a01c3b5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -620,8 +620,8 @@ static inline void rmv_page_order(struct page *page)
  *
  * For recording page's order, we use page_private(page).
  */
-static inline int page_is_buddy(struct page *page, struct page *buddy,
-                                                       unsigned int order)
+static inline int page_is_buddy(struct zone *zone, struct page *page,
+                               struct page *buddy, unsigned int order)
 {
        if (!pfn_valid_within(page_to_pfn(buddy)))
                return 0;
@@ -644,6 +644,12 @@ static inline int page_is_buddy(struct page *page, struct page *buddy,
                if (page_zone_id(page) != page_zone_id(buddy))
                        return 0;
 
+               if (IS_ENABLED(CONFIG_CMA) &&
+                       has_isolate_pageblock(zone) &&
+                       order >= pageblock_order &&
+                       is_migrate_isolate(get_pageblock_migratetype(buddy)))
+                       return 0;
+
                VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
 
                return 1;
@@ -711,7 +717,7 @@ static inline void __free_one_page(struct page *page,
        while (order < max_order - 1) {
                buddy_idx = __find_buddy_index(page_idx, order);
                buddy = page + (buddy_idx - page_idx);
-               if (!page_is_buddy(page, buddy, order))
+               if (!page_is_buddy(zone, page, buddy, order))
                        break;
                /*
                 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
@@ -745,7 +751,7 @@ static inline void __free_one_page(struct page *page,
                higher_page = page + (combined_idx - page_idx);
                buddy_idx = __find_buddy_index(combined_idx, order + 1);
                higher_buddy = higher_page + (buddy_idx - combined_idx);
-               if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
+               if (page_is_buddy(zone, higher_page, higher_buddy, order + 1)) {
                        list_add_tail(&page->lru,
                                &zone->free_area[order].free_list[migratetype]);
                        goto out;
-- 
1.9.1