From bec433f29537652ed054148edfd7e2183ddcf7c3 Mon Sep 17 00:00:00 2001
From: "T.J. Alumbaugh" <talumbau@google.com>
Date: Wed, 18 Jan 2023 00:18:25 +0000
Subject: [PATCH 16/19] UPSTREAM: mm: multi-gen LRU: improve
 lru_gen_exit_memcg()

Add warnings and poison ->next.

Link: https://lkml.kernel.org/r/20230118001827.1040870-6-talumbau@google.com
Change-Id: I53de9e04c1ae941e122b33cd45d2bbb5f34aae0c
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 37cc99979d04cca677c0ad5c0acd1149ec165d1b)
Bug: 274865848
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
 mm/vmscan.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -6172,12 +6172,17 @@ void lru_gen_exit_memcg(struct mem_cgrou
 	int i;
 	int nid;
 
+	VM_WARN_ON_ONCE(!list_empty(&memcg->mm_list.fifo));
+
 	for_each_node(nid) {
 		struct lruvec *lruvec = get_lruvec(memcg, nid);
 
+		VM_WARN_ON_ONCE(lruvec->mm_state.nr_walkers);
 		VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0,
 					   sizeof(lruvec->lrugen.nr_pages)));
 
+		lruvec->lrugen.list.next = LIST_POISON1;
+
 		for (i = 0; i < NR_BLOOM_FILTERS; i++) {
 			bitmap_free(lruvec->mm_state.filters[i]);
 			lruvec->mm_state.filters[i] = NULL;
