diff options
| author | SeongJae Park <sj@kernel.org> | 2023-10-19 19:49:24 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-25 16:47:15 -0700 |
| commit | 62f76a7b53bfa2ecfe1570a5b1d0d574c576a56d (patch) | |
| tree | 85df0492bcf83435b53bf99daf924ac4a1898550 /mm/damon | |
| parent | 44063f125af4bb4efd1d500d8091fa33a98af325 (diff) | |
mm/damon/core: avoid divide-by-zero from pseudo-moving window length calculation
When calculating the pseudo-moving access rate, DAMON 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.
Note that this is a fix for a commit that not in the mainline but mm
tree.
Link: https://lkml.kernel.org/r/20231019194924.100347-6-sj@kernel.org
Fixes: ace30fb21af5 ("mm/damon/core: use pseudo-moving sum for nr_accesses_bp")
Reported-by: Jakub Acs <acsjakub@amazon.de>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/damon')
| -rw-r--r-- | mm/damon/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c index e194c8075235..aa2dc7087cd9 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1665,7 +1665,7 @@ void damon_update_region_access_rate(struct damon_region *r, bool accessed, * aggr_interval, owing to validation of damon_set_attrs(). */ if (attrs->sample_interval) - len_window = attrs->aggr_interval / attrs->sample_interval; + len_window = damon_max_nr_accesses(attrs); r->nr_accesses_bp = damon_moving_sum(r->nr_accesses_bp, r->last_nr_accesses * 10000, len_window, accessed ? 10000 : 0); |