From aadc45fae64865c47a579bed2b45bee2b97df519 Mon Sep 17 00:00:00 2001
From: Yu Zhao <yuzhao@google.com>
Date: Fri, 2 Oct 2020 02:08:58 -0600
Subject: [PATCH] BACKPORT: mm: VM_BUG_ON lru page flags

Move scattered VM_BUG_ONs to two essential places that cover all
lru list additions and deletions.

Link: https://lore.kernel.org/linux-mm/20201207220949.830352-8-yuzhao@google.com/
Link: https://lkml.kernel.org/r/20210122220600.906146-8-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit bc7112719e1e80e4208eef3fc9bd8d2b6c263e7d)
Bug: 227651406
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Change-Id: I950ad4171f973c740d9fc3778d44efc020d0e12c
---
 include/linux/mm_inline.h | 4 ++++
 mm/swap.c                 | 2 --
 mm/vmscan.c               | 1 -
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index ceefe6988e9d..3ca82456b4dd 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -67,6 +67,8 @@ static inline enum lru_list page_lru_base_type(struct page *page)
  */
 static __always_inline void __clear_page_lru_flags(struct page *page)
 {
+	VM_BUG_ON_PAGE(!PageLRU(page), page);
+
 	__ClearPageLRU(page);
 
 	/* this shouldn't happen, so leave the flags to bad_page() */
@@ -88,6 +90,8 @@ static __always_inline enum lru_list page_lru(struct page *page)
 {
 	enum lru_list lru;
 
+	VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
+
 	if (PageUnevictable(page))
 		lru = LRU_UNEVICTABLE;
 	else {
diff --git a/mm/swap.c b/mm/swap.c
index 24ca3e52b527..f2f04faba70c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -87,7 +87,6 @@ static void __page_cache_release(struct page *page)
 
 		spin_lock_irqsave(&pgdat->lru_lock, flags);
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		VM_BUG_ON_PAGE(!PageLRU(page), page);
 		del_page_from_lru_list(page, lruvec);
 		__clear_page_lru_flags(page);
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -1040,7 +1039,6 @@ void release_pages(struct page **pages, int nr)
 			}
 
 			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
-			VM_BUG_ON_PAGE(!PageLRU(page), page);
 			del_page_from_lru_list(page, lruvec);
 			__clear_page_lru_flags(page);
 		}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6e8bf535a66b..f102ca3eeac5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4417,7 +4417,6 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 			continue;
 
 		if (page_evictable(page)) {
-			VM_BUG_ON_PAGE(PageActive(page), page);
 			del_page_from_lru_list(page, lruvec);
 			ClearPageUnevictable(page);
 			add_page_to_lru_list(page, lruvec);