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From:   Kefeng Wang <wangkefeng.wang@huawei.com>
To:     SeongJae Park <sj@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        <damon@lists.linux.dev>, <linux-mm@kvack.org>
CC:     <linux-kernel@vger.kernel.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        <syzbot+841a46899768ec7bec67@syzkaller.appspotmail.com>
Subject: [PATCH] mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()
Date:   Sat, 27 May 2023 10:33:30 +0800
Message-ID: <20230527023330.23535-1-wangkefeng.wang@huawei.com>
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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@syzkaller.appspotmail.com
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 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