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

From: Kefeng Wang
Date: Fri May 26 2023 - 22:17:38 EST

If 'aggr_interval' is smaller than 'sample_interval', max_nr_accesses becomes
zero which leads to divide error in damon_nr_accesses_to_accesses_bp(), 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
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
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;