mm/page_alloc: add a VM_BUG in __free_one_page() if the zone is uninitialized.

Freeing pages to uninitialized zones is not handled by
__free_one_page(), and should never happen when the code is correct.

Ran into this while writing some code that dynamically onlines extra
zones.

Signed-off-by: Cody P Schafer <[email protected]>
Cc: David Hansen <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a3687afc5917cd84b842f450b7cf400ffd57d4b4..9614aabee8c5bb20af749eebb68c9f61f8e027be 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -538,6 +538,8 @@ static inline void __free_one_page(struct page *page,
        unsigned long uninitialized_var(buddy_idx);
        struct page *buddy;
 
+       VM_BUG_ON(!zone_is_initialized(zone));
+
        if (unlikely(PageCompound(page)))
                if (unlikely(destroy_compound_page(page, order)))
                        return;