mm: hugetlbfs: Add some VM_BUG_ON()s to catch non-hugetlbfs pages

Dave Jiang reported that he was seeing oopses when running NUMA systems
and default_hugepagesz=1G.  I traced the issue down to
migrate_page_copy() trying to use the same code for hugetlb pages and
transparent hugepages.  It should not have been trying to pass thp pages
in there.

So, add some VM_BUG_ON()s for the next hapless VM developer that tries
the same thing.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index bd7e987522221f42b7042cc242abc8ca31a72996..251233c1494df793ae7d9d90e4bc5ed5e794ab28 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -360,6 +360,7 @@ static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 
 static inline struct hstate *page_hstate(struct page *page)
 {
+       VM_BUG_ON(!PageHuge(page));
        return size_to_hstate(PAGE_SIZE << compound_order(page));
 }