[PATCH v2] mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()

From: Kefeng Wang
Date: Fri May 26 2023 - 23:04:58 EST


If 'aggr_interval' is smaller than 'sample_interval', max_nr_accesses
in damon_nr_accesses_to_accesses_bp() becomes zero which leads to divide
error, let's validate the values of them in damon_set_attrs() to fix it,
which similar to others attrs check.

Reported-by: syzbot+841a46899768ec7bec67@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=841a46899768ec7bec67
Link: https://lore.kernel.org/damon/00000000000055fc4e05fc975bc2@xxxxxxxxxx/
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Cc: <stable@xxxxxxxxxxxxxxx> # 6.3.x-
Reviewed-by: SeongJae Park <sj@xxxxxxxxxx>
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
v2: close checkpatch warning, add RB/cc stable, per SJ

mm/damon/core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index d9ef62047bf5..91cff7f2997e 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -551,6 +551,8 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs)
return -EINVAL;
if (attrs->min_nr_regions > attrs->max_nr_regions)
return -EINVAL;
+ if (attrs->sample_interval > attrs->aggr_interval)
+ return -EINVAL;

damon_update_monitoring_results(ctx, attrs);
ctx->attrs = *attrs;
--
2.35.3