diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index dd4ece37269..1cffc223bff 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -23,15 +23,15 @@
 int string_get_size(u64 size, const enum string_size_units units,
 		    char *buf, int len)
 {
-	const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
+	static const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
 				   "EB", "ZB", "YB", NULL};
-	const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
+	static const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
 				 "EiB", "ZiB", "YiB", NULL };
-	const char **units_str[] = {
+	static const char **units_str[] = {
 		[STRING_UNITS_10] =  units_10,
 		[STRING_UNITS_2] = units_2,
 	};
-	const unsigned int divisor[] = {
+	static const unsigned int divisor[] = {
 		[STRING_UNITS_10] = 1000,
 		[STRING_UNITS_2] = 1024,
 	};