mm/huge_memory.c: use head to check huge zero page

The page could be a tail page, if this is the case, this BUG_ON will
never be triggered.

Link: http://lkml.kernel.org/r/20200110032610.26499-1-richardw.yang@linux.intel.com
Fixes: e9b61f19858a ("thp: reintroduce split_huge_page()")

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a880932136740ddbc6bbf1b4b5c04bfd74f9c8ef..ee1dafedd8fe82ef7ebf4941e6c4ce9eb256ae5e 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2712,7 +2712,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
        unsigned long flags;
        pgoff_t end;
 
-       VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
+       VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
        VM_BUG_ON_PAGE(!PageLocked(page), page);
        VM_BUG_ON_PAGE(!PageCompound(page), page);