[PATCH] mm: Add conditions to avoid out-of-bounds

[nixiaoming]

In the function memcg_init_list_lru
if call goto fail when i == 0, will cause out-of-bounds at lru->node[i]

The same out-of-bounds access scenario exists in the functions
memcg_update_list_lru and __memcg_init_list_lru_node

Signed-off-by: nixiaoming <nixiaom...@huawei.com>
---
 mm/list_lru.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/list_lru.c b/mm/list_lru.c
index fcfb6c8..ec6bdd9 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -298,6 +298,9 @@ static void __memcg_destroy_list_lru_node(struct 
list_lru_memcg *memcg_lrus,
 {
        int i;
 
+       if (unlikely(begin >= end))
+               return;
+
        for (i = begin; i < end; i++)
                kfree(memcg_lrus->lru[i]);
 }
@@ -422,6 +425,8 @@ static int memcg_init_list_lru(struct list_lru *lru, bool 
memcg_aware)
        }
        return 0;
 fail:
+       if (unlikely(i == 0))
+               return -ENOMEM;
        for (i = i - 1; i >= 0; i--) {
                if (!lru->node[i].memcg_lrus)
                        continue;
@@ -456,6 +461,8 @@ static int memcg_update_list_lru(struct list_lru *lru,
        }
        return 0;
 fail:
+       if (unlikely(i == 0))
+               return -ENOMEM;
        for (i = i - 1; i >= 0; i--) {
                if (!lru->node[i].memcg_lrus)
                        continue;
-- 
2.10.1