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| author | SeongJae Park <sj@kernel.org> | 2023-10-19 21:49:21 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-26 01:47:15 +0200 |
| commit | d35963bfb05877455228ecec6b194f624489f96a (patch) | |
| tree | 6ffa5dc3d756612c92fa5a33592aada553e8cd77 /mm | |
| parent | mm/damon: implement a function for max nr_accesses safe calculation (diff) | |
| download | linux-d35963bfb05877455228ecec6b194f624489f96a.tar.xz linux-d35963bfb05877455228ecec6b194f624489f96a.zip | |
mm/damon/core: avoid divide-by-zero during monitoring results update
When monitoring attributes are changed, DAMON updates access rate of the
monitoring results accordingly. For that, it 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/20231019194924.100347-3-sj@kernel.org
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> [6.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/damon/core.c | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c index 9f4f7c378cf3..e194c8075235 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -500,20 +500,14 @@ static unsigned int damon_age_for_new_attrs(unsigned int age, static unsigned int damon_accesses_bp_to_nr_accesses( unsigned int accesses_bp, struct damon_attrs *attrs) { - unsigned int max_nr_accesses = - attrs->aggr_interval / attrs->sample_interval; - - return accesses_bp * max_nr_accesses / 10000; + return accesses_bp * damon_max_nr_accesses(attrs) / 10000; } /* convert nr_accesses to access ratio in bp (per 10,000) */ static unsigned int damon_nr_accesses_to_accesses_bp( unsigned int nr_accesses, struct damon_attrs *attrs) { - unsigned int max_nr_accesses = - attrs->aggr_interval / attrs->sample_interval; - - return nr_accesses * 10000 / max_nr_accesses; + return nr_accesses * 10000 / damon_max_nr_accesses(attrs); } static unsigned int damon_nr_accesses_for_new_attrs(unsigned int nr_accesses, |