diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
index 18fccc303db7..bfd75be6d415 100644
--- a/arch/s390/mm/extmem.c
+++ b/arch/s390/mm/extmem.c
@@ -79,7 +79,7 @@ struct qin64 {
 struct dcss_segment {
 	struct list_head list;
 	char dcss_name[8];
-	char res_name[15];
+	char res_name[16];
 	unsigned long start_addr;
 	unsigned long end;
 	atomic_t ref_count;
@@ -434,7 +434,7 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
 	memcpy(&seg->res_name, seg->dcss_name, 8);
 	EBCASC(seg->res_name, 8);
 	seg->res_name[8] = '\0';
-	strncat(seg->res_name, " (DCSS)", 7);
+	strlcat(seg->res_name, " (DCSS)", sizeof(seg->res_name));
 	seg->res->name = seg->res_name;
 	rc = seg->vm_segtype;
 	if (rc == SEG_TYPE_SC ||