6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: SeongJae Park <sj@xxxxxxxxxx> commit 44063f125af4bb4efd1d500d8091fa33a98af325 upstream. When calculating the hotness threshold for lru_prio scheme of DAMON_LRU_SORT, the module divides some values by the maximum nr_accesses. However, due to the type of the related variables, simple division-based calculation of the divisor can return zero. As a result, divide-by-zero is possible. Fix it by using damon_max_nr_accesses(), which handles the case. Link: https://lkml.kernel.org/r/20231019194924.100347-5-sj@xxxxxxxxxx Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting") Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> Reported-by: Jakub Acs <acsjakub@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [6.0+] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/damon/lru_sort.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/mm/damon/lru_sort.c +++ b/mm/damon/lru_sort.c @@ -193,9 +193,7 @@ static int damon_lru_sort_apply_paramete if (err) return err; - /* aggr_interval / sample_interval is the maximum nr_accesses */ - hot_thres = damon_lru_sort_mon_attrs.aggr_interval / - damon_lru_sort_mon_attrs.sample_interval * + hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) * hot_thres_access_freq / 1000; scheme = damon_lru_sort_new_hot_scheme(hot_thres); if (!scheme)
