diff --git a/kernel/resource.c b/kernel/resource.c
index 35c99ac02c7c..52f696f11adf 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -266,7 +266,7 @@ static int find_resource(struct resource *root, struct resource *new,
 		new->start = (new->start + align - 1) & ~(align - 1);
 		if (alignf)
 			alignf(alignf_data, new, size, align);
-		if (new->start < new->end && new->end - new->start + 1 >= size) {
+		if (new->start < new->end && new->end - new->start >= size - 1) {
 			new->end = new->start + size - 1;
 			return 0;
 		}