[PATCH 05/18] Various VM_BUG_ON for securing tail pages usage

["Radosław Smogura" <mail@smogura.eu>]

Signed-off-by: Radosław Smogura <mail@smogura.eu>
---
 mm/vmscan.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c52b235..7299b71 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -636,7 +636,7 @@ void putback_lru_page(struct page *page)
 	int was_unevictable = PageUnevictable(page);
 
 	VM_BUG_ON(PageLRU(page));
-
+	VM_BUG_ON(PageTail(page));
 redo:
 	ClearPageUnevictable(page);
 
@@ -1177,6 +1177,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		prefetchw_prev_lru_page(page, src, flags);
 
 		VM_BUG_ON(!PageLRU(page));
+		VM_BUG_ON(PageTail(page));
 
 		switch (__isolate_lru_page(page, mode, file)) {
 		case 0:
@@ -1239,6 +1240,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 			if (__isolate_lru_page(cursor_page, mode, file) == 0) {
 				unsigned int isolated_pages;
 
+				VM_BUG_ON(PageTail(cursor_page));
+
 				mem_cgroup_lru_del(cursor_page);
 				list_move(&cursor_page->lru, dst);
 				isolated_pages = hpage_nr_pages(cursor_page);
-- 
1.7.3.4

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