euleros inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7JI6K CVE: NA

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In the swapcache recycling process, the number of pages to be reclaimed on each node is obtained as follows:

nr_to_reclaim[nid_num] = (swapcache_to_reclaim / (swapcache_total_reclaimable / nr[nid_num]));

However, nr[nid_num] is obtained by traversing the number of swapcache pages on each node. If there are multiple nodes in the environment and no swap process occurs on a node, no swapcache page exists. The value of nr[nid_num] may be 0.

Therefore, division by zero errors may occur.

Signed-off-by: liubo liubo254@huawei.com --- mm/vmscan.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c index f5671facdc51..00ed94bfea78 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4819,9 +4819,12 @@ int do_swapcache_reclaim(unsigned long *swapcache_watermark, for_each_node_state(nid, N_MEMORY) { cond_resched();

- nr_to_reclaim[nid_num] = (swapcache_to_reclaim / (swapcache_total_reclaimable / nr[nid_num])); + nr_to_reclaim[nid_num] = (swapcache_total_reclaimable == 0) ? 0 : + ((swapcache_to_reclaim * nr[nid_num]) / + swapcache_total_reclaimable); reclaim_page_count += reclaim_swapcache_pages_from_list(nid, - &swapcache_list[nid_num], nr_to_reclaim[nid_num], false); + &swapcache_list[nid_num], + nr_to_reclaim[nid_num], false); nid_num++; }