diff --git a/executer/kernel/mcctrl/control.c b/executer/kernel/mcctrl/control.c
index 6b2f603c..de034ca2 100644
--- a/executer/kernel/mcctrl/control.c
+++ b/executer/kernel/mcctrl/control.c
@@ -3132,7 +3132,7 @@ static long
 mcexec_uti_attr(ihk_os_t os, struct uti_attr_desc __user *_desc)
 {
 	struct uti_attr_desc desc;
-	char *uti_cpu_set_str;
+	char *uti_cpu_set_str = NULL;
 	struct kuti_attr *kattr;
 	cpumask_t *cpuset = NULL, *env_cpuset = NULL;
 	struct mcctrl_usrdata *ud = ihk_host_os_get_usrdata(os);
@@ -3167,18 +3167,20 @@ mcexec_uti_attr(ihk_os_t os, struct uti_attr_desc __user *_desc)
 		goto out;
 	}
 
-	if (!(uti_cpu_set_str = kmalloc(desc.uti_cpu_set_len, GFP_KERNEL))) {
-		pr_err("%s: error: allocating uti_cpu_set_str\n",
-		       __func__);
-		rc = -ENOMEM;
-		goto out;
-	}
+	if (desc.uti_cpu_set_str) {
+		if (!(uti_cpu_set_str = kmalloc(desc.uti_cpu_set_len, GFP_KERNEL))) {
+			pr_err("%s: error: allocating uti_cpu_set_str\n",
+			       __func__);
+			rc = -ENOMEM;
+			goto out;
+		}
 
-	if ((rc = copy_from_user(uti_cpu_set_str, desc.uti_cpu_set_str, desc.uti_cpu_set_len))) {
-		pr_err("%s: error: copy_from_user\n",
-		       __func__);
-		rc = -EFAULT;
-		goto out;
+		if ((rc = copy_from_user(uti_cpu_set_str, desc.uti_cpu_set_str, desc.uti_cpu_set_len))) {
+			pr_err("%s: error: copy_from_user\n",
+			       __func__);
+			rc = -EFAULT;
+			goto out;
+		}
 	}
 
 	kattr = phys_to_virt(desc.phys_attr);
diff --git a/executer/user/mcexec.c b/executer/user/mcexec.c
index 6494afba..aae25353 100644
--- a/executer/user/mcexec.c
+++ b/executer/user/mcexec.c
@@ -3030,7 +3030,9 @@ static long util_thread(struct thread_data_s *my_thread,
 
 		desc.phys_attr = pattr;
 		desc.uti_cpu_set_str = getenv("UTI_CPU_SET");
-		desc.uti_cpu_set_len = strlen(desc.uti_cpu_set_str) + 1;
+		if (desc.uti_cpu_set_str) {
+			desc.uti_cpu_set_len = strlen(desc.uti_cpu_set_str) + 1;
+		}
 
 		if ((rc = ioctl(fd, MCEXEC_UP_UTI_ATTR, &desc))) {
 			fprintf(stderr, "%s: error: MCEXEC_UP_UTI_ATTR: %s\n",