Commit ab1f306f authored by Yu Zhao's avatar Yu Zhao Committed by Linus Torvalds

mm: verify compound order when freeing a page

This allows us to catch the bug fixed in the previous patch (mm: free
compound page with correct order).

Here we also verify whether a page is tail page or not -- tail pages are
supposed to be freed along with their head, not by themselves.
Signed-off-by: default avatarYu Zhao <yuzhao@google.com>
Reviewed-by: default avatar"Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d7be003a
......@@ -741,6 +741,9 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
int i;
int bad = 0;
VM_BUG_ON_PAGE(PageTail(page), page);
VM_BUG_ON_PAGE(PageHead(page) && compound_order(page) != order, page);
trace_mm_page_free(page, order);
kmemcheck_free_shadow(page, order);
......
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