diff options
| author | SeongJae Park <sj@kernel.org> | 2023-10-19 22:49:22 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-11-28 20:07:09 +0300 |
| commit | 834a800c58ea494483d63aa077debfef3ac7199f (patch) | |
| tree | 2085789d6887b4a72e8c6275c58063ae609737c9 /mm | |
| parent | 2b38f0dbe8ba12da6985646921d531dce9b3489b (diff) | |
| download | linux-834a800c58ea494483d63aa077debfef3ac7199f.tar.xz | |
mm/damon/ops-common: avoid divide-by-zero during region hotness calculation
commit 3bafc47d3c4a2fc4d3b382aeb3c087f8fc84d9fd upstream.
When calculating the hotness of each region for the under-quota regions
prioritization, 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.
Link: https://lkml.kernel.org/r/20231019194924.100347-4-sj@kernel.org
Fixes: 198f0f4c58b9 ("mm/damon/vaddr,paddr: support pageout prioritization")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> [5.16+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/damon/ops-common.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c index 13b99975cbc2..0b75a8d5c706 100644 --- a/mm/damon/ops-common.c +++ b/mm/damon/ops-common.c @@ -87,7 +87,6 @@ void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr int damon_hot_score(struct damon_ctx *c, struct damon_region *r, struct damos *s) { - unsigned int max_nr_accesses; int freq_subscore; unsigned int age_in_sec; int age_in_log, age_subscore; @@ -95,8 +94,8 @@ int damon_hot_score(struct damon_ctx *c, struct damon_region *r, unsigned int age_weight = s->quota.weight_age; int hotness; - max_nr_accesses = c->attrs.aggr_interval / c->attrs.sample_interval; - freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses; + freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / + damon_max_nr_accesses(&c->attrs); age_in_sec = (unsigned long)r->age * c->attrs.aggr_interval / 1000000; for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec; |