DAMON region end address is exclusive one, but charge_addr_from is
assigned assuming the end address is inclusive. As a result, DAMOS
action to next up to min_region_sz memory can be skipped. This is quite
negligible user impact. But, the bug is a bug that can be very simply
fixed. Fix the wrong assignment to respect the exclusiveness of the
address.
The issue was discovered [1] by Sashiko.
[1] https://lore.kernel.org/20260428032324.115663-1-sj@kernel.org
Fixes: 50585192bc2e ("mm/damon/schemes: skip already charged targets and regions")
Cc: <stable@vger.kernel.org> # 5.16.x
Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 278594847cf94..37c9a40d0577b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2107,7 +2107,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
if (damos_quota_is_set(quota) &&
quota->charged_sz >= quota->esz) {
quota->charge_target_from = t;
- quota->charge_addr_from = r->ar.end + 1;
+ quota->charge_addr_from = r->ar.end;
}
}
if (s->action != DAMOS_STAT)
base-commit: 986c714ac6faa9750e15ccaec72ff2823c96a5c6
--
2.47.3