FAILED: patch "[PATCH] mm/damon/reclaim: avoid divide-by-zero in" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] mm/damon/reclaim: avoid divide-by-zero in" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x e6b543ca9806d7bced863f43020e016ee996c057
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025091328-reversing-judiciary-ca17@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e6b543ca9806d7bced863f43020e016ee996c057 Mon Sep 17 00:00:00 2001
From: Quanmin Yan <yanquanmin1@huawei.com>
Date: Wed, 27 Aug 2025 19:58:58 +0800
Subject: [PATCH] mm/damon/reclaim: avoid divide-by-zero in
 damon_reclaim_apply_parameters()

When creating a new scheme of DAMON_RECLAIM, the calculation of
'min_age_region' uses 'aggr_interval' as the divisor, which may lead to
division-by-zero errors.  Fix it by directly returning -EINVAL when such a
case occurs.

Link: https://lkml.kernel.org/r/20250827115858.1186261-3-yanquanmin1@huawei.com
Fixes: f5a79d7c0c87 ("mm/damon: introduce struct damos_access_pattern")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index 3c71b4596676..fb7c982a0018 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -194,6 +194,11 @@ static int damon_reclaim_apply_parameters(void)
 	if (err)
 		return err;
 
+	if (!damon_reclaim_mon_attrs.aggr_interval) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	err = damon_set_attrs(param_ctx, &damon_reclaim_mon_attrs);
 	if (err)
 		goto out;

[PATCH 6.6.y] mm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()

[SeongJae Park]

From: Quanmin Yan <yanquanmin1@huawei.com>

When creating a new scheme of DAMON_RECLAIM, the calculation of
'min_age_region' uses 'aggr_interval' as the divisor, which may lead to
division-by-zero errors.  Fix it by directly returning -EINVAL when such a
case occurs.

Link: https://lkml.kernel.org/r/20250827115858.1186261-3-yanquanmin1@huawei.com
Fixes: f5a79d7c0c87 ("mm/damon: introduce struct damos_access_pattern")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit e6b543ca9806d7bced863f43020e016ee996c057)
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/reclaim.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index 66e190f0374a..586daa2cefe4 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -167,6 +167,9 @@ static int damon_reclaim_apply_parameters(void)
 	struct damos_filter *filter;
 	int err = 0;
 
+	if (!damon_reclaim_mon_attrs.aggr_interval)
+		return -EINVAL;
+
 	err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
 	if (err)
 		return err;
-- 
2.39.5