From: Wei Yang <richardw.yang@linux.intel.com>
Date: Fri, 31 Jan 2020 06:14:29 +0000 (-0800)
Subject: mm/huge_memory.c: use head to check huge zero page
X-Git-Tag: v4.9.216~40
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b259672e3ae1699b3b91423505afa19ebd98c59d;p=thirdparty%2Fkernel%2Fstable.git

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

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>
---

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f32f73fa5d3a1..5fbd77d52602a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2095,7 +2095,7 @@ 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(!PageSwapBacked(page), page);
 	VM_BUG_ON_PAGE(!PageCompound(page), page);