From: SeongJae Park <sj@kernel.org>
Date: Sat, 7 Mar 2026 19:49:14 +0000 (-0800)
Subject: mm/damon/core: use time_after_eq() in kdamond_fn()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23754a36cd1ce888a136c762080c89e4d7b364d9;p=thirdparty%2Fkernel%2Flinux.git

mm/damon/core: use time_after_eq() in kdamond_fn()

damon_ctx->passed_sample_intervals and damon_ctx->next_*_sis are unsigned
long.  Those are compared in kdamond_fn() using normal comparison
operators.  It is unsafe from overflow.  Use time_after_eq(), which is
safe from overflows when correctly used, instead.

Link: https://lkml.kernel.org/r/20260307194915.203169-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/damon/core.c b/mm/damon/core.c
index ac06465cd9eb4..0c167bbc9c1c4 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2921,7 +2921,8 @@ static int kdamond_fn(void *data)
 		if (ctx->ops.check_accesses)
 			max_nr_accesses = ctx->ops.check_accesses(ctx);
 
-		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_aggregation_sis)) {
 			kdamond_merge_regions(ctx,
 					max_nr_accesses / 10,
 					sz_limit);
@@ -2943,10 +2944,12 @@ static int kdamond_fn(void *data)
 
 		sample_interval = ctx->attrs.sample_interval ?
 			ctx->attrs.sample_interval : 1;
-		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_aggregation_sis)) {
 			if (ctx->attrs.intervals_goal.aggrs &&
-					ctx->passed_sample_intervals >=
-					ctx->next_intervals_tune_sis) {
+					time_after_eq(
+						ctx->passed_sample_intervals,
+						ctx->next_intervals_tune_sis)) {
 				/*
 				 * ctx->next_aggregation_sis might be updated
 				 * from kdamond_call().  In the case,
@@ -2980,7 +2983,8 @@ static int kdamond_fn(void *data)
 			kdamond_split_regions(ctx);
 		}
 
-		if (ctx->passed_sample_intervals >= next_ops_update_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_ops_update_sis)) {
 			ctx->next_ops_update_sis = next_ops_update_sis +
 				ctx->attrs.ops_update_interval /
 				sample_interval;