This is a note to let you know that I've just added the patch titled
mm/damon/lru_sort: avoid divide-by-zero in hot threshold calculation
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 44063f125af4bb4efd1d500d8091fa33a98af325 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@xxxxxxxxxx>
Date: Thu, 19 Oct 2023 19:49:23 +0000
Subject: mm/damon/lru_sort: avoid divide-by-zero in hot threshold calculation
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
@@ -195,9 +195,7 @@ 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)
Patches currently in stable-queue which might be from sj@xxxxxxxxxx are
queue-6.1/mm-damon-implement-a-function-for-max-nr_accesses-safe-calculation.patch
queue-6.1/mm-damon-ops-common-avoid-divide-by-zero-during-region-hotness-calculation.patch
queue-6.1/mm-damon-sysfs-check-error-from-damon_sysfs_update_target.patch
queue-6.1/mm-damon-lru_sort-avoid-divide-by-zero-in-hot-threshold-calculation.patch
queue-6.1/mm-damon-sysfs-update-monitoring-target-regions-for-online-input-commit.patch
queue-6.1/mm-damon-sysfs-remove-requested-targets-when-online-commit-inputs.patch
