diff options
| author | Honggyu Kim <honggyu.kim@sk.com> | 2025-07-02 09:02:04 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-09 21:07:55 -0700 |
| commit | bd225b9591442065beb876da72656f4a2d627d03 (patch) | |
| tree | ed3d351bbec8bf8869badf63f8a31b9578e7defc | |
| parent | ddba1b6cf4791824f8b614ff8878353a6c6f79f5 (diff) | |
mm/damon: fix divide by zero in damon_get_intervals_score()
The current implementation allows having zero size regions with no special
reasons, but damon_get_intervals_score() gets crashed by divide by zero
when the region size is zero.
[ 29.403950] Oops: divide error: 0000 [#1] SMP NOPTI
This patch fixes the bug, but does not disallow zero size regions to keep
the backward compatibility since disallowing zero size regions might be a
breaking change for some users.
In addition, the same crash can happen when intervals_goal.access_bp is
zero so this should be fixed in stable trees as well.
Link: https://lkml.kernel.org/r/20250702000205.1921-5-honggyu.kim@sk.com
Fixes: f04b0fedbe71 ("mm/damon/core: implement intervals auto-tuning")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/damon/core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c index bc2e58c1222d..979b29e16ef4 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1449,6 +1449,7 @@ static unsigned long damon_get_intervals_score(struct damon_ctx *c) } } target_access_events = max_access_events * goal_bp / 10000; + target_access_events = target_access_events ? : 1; return access_events * 10000 / target_access_events; } |