diff --git a/src/mem/mem_pool.c b/src/mem/mem_pool.c
index 3ac6a61bf..10f20e61a 100644
--- a/src/mem/mem_pool.c
+++ b/src/mem/mem_pool.c
@@ -165,8 +165,8 @@ struct mem_pool_entry *mem_pool_borrow(struct mem_pool *pool)
 	if (!pool)
 		return NULL;
 
-	for (size_t i = re_atomic_acq(&pool->next_free); i < pool->nmemb;
-	     i++) {
+	for (size_t i = (size_t)re_atomic_acq(&pool->next_free);
+	     i < pool->nmemb; i++) {
 		if (!re_atomic_acq(&pool->objs[i].used)) {
 			re_atomic_rls_set(&pool->objs[i].used, true);
 			re_atomic_rls_set(&pool->next_free, i + 1);