releases/5.5.8/mm-huge_memory.c-use-head-to-check-huge-zero-page.patch

From cb829624867b5ab10bc6a7036d183b1b82bfe9f8 Mon Sep 17 00:00:00 2001
From: Wei Yang <richardw.yang@linux.intel.com>
Date: Thu, 30 Jan 2020 22:14:29 -0800
Subject: mm/huge_memory.c: use head to check huge zero page

From: Wei Yang <richardw.yang@linux.intel.com>

commit cb829624867b5ab10bc6a7036d183b1b82bfe9f8 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/huge_memory.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2712,7 +2712,7 @@ int split_huge_page_to_list(struct page
 	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);