diff --git a/drivers/gpu/drm/tests/drm_buddy_test.c b/drivers/gpu/drm/tests/drm_buddy_test.c
index f8ee714df396..09ee6f6af896 100644
--- a/drivers/gpu/drm/tests/drm_buddy_test.c
+++ b/drivers/gpu/drm/tests/drm_buddy_test.c
@@ -89,7 +89,8 @@ static int check_block(struct kunit *test, struct drm_buddy *mm,
 		err = -EINVAL;
 	}
 
-	if (!is_power_of_2(block_size)) {
+	/* We can't use is_power_of_2() for a u64 on 32-bit systems. */
+	if (block_size & (block_size - 1)) {
 		kunit_err(test, "block size not power of two\n");
 		err = -EINVAL;
 	}